Ancient Astronauts

Tomorrow's lesson: clubbing your enemies with the sticks.

Mary: Did you build the Pyramids?
Dick: Only the one in Las Vegas.
Mary: What about Easter Island?
Dick: Easter Island was a practical joke that got out of hand.

— 3rd Rock from the Sun, "The Thing That Wouldn't Die: Part 1"

Science Fiction trope wherein ancient locations, legends, gods, and creatures from ancient myth are connected to alien visitors from a radically more advanced civilization. This trope includes that these aliens influenced our history in some way, mostly through technological advances. Often these aliens are sufficiently advanced.

When this trope kicks in, expect various myths to be related to aliens. Everyone knows about Clarke's Third Law: the many legends of magic, gods, beings coming from the sky and the like were based on alien technology that we could not comprehend at that time.

Proponents of this theory also espouse that ancient construction projects like the pyramids and Stonehenge are clearly too advanced and a little too fantastic for ancient man to have constructed without help from a more advanced civilization. Or that since there are pyramids in the Americas, Egypt, and China... you guessed it, they all got their idea from aliens. Other popular sites include the Moai of Easter Island and the Nazca Lines.

Popularized by Erich von Däniken's 1968 book Chariots of the Gods? and its various sequels, which stridently insist that a careful blend of selected archaeological evidence will reveal that this very scenario happened in reality. The Real Life evidence for this is little but if it's brought up in fiction, expect these theories to be always right on the money. After all, it's not like either aliens or ancient humans would be interesting enough to write fiction about on their own, without them interacting, would they?

This theory is often crossed over with Atlantis. Essentially runs on God Guise. May result in Boldly Coming. When the aliens were the inspiration for our myths and legends, that makes their home planet Where the Magic Went. If the unknown ancestors sport special abilities which aren't derived from technology, compare Our Ancestors Are Superheroes. Usually overlaps with Neglectful Precursors, as the aliens are generally implied to have lost interest in humans and/or concluded we're unworthy successors, ages ago. Sub-Trope of All Theories Are True. See also Beethoven Was an Alien Spy, for individuals rather than entire societies.

Ancient Astronauts are very frequently builders/users of Sufficiently Advanced Bamboo Technology.

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Examples:

Anime and Manga

• In Babel II the Tower of Babel was built under the guidance of Babel I, an alien who fell on Earth and who wanted to use the tower to send an amplified message of help to be rescued. When that project failed, he remained on Earth, mating with humans and leaving his technology in the ruins of the tower for the first of his descendants who proved to be worthy enough.
• GoShogun The Big Bad, Neoneros, is revealed to be one at in the final episode, claiming to be with humanity for ten thousand years.
• Urusei Yatsura presents a number of beings from Japanese myth as aliens.
• Nadia: The Secret of Blue Water utilizes the Atlantean subtrope.
• In the manga version of Chrono Crusade, this is what the demons actually are — aliens. Their world was destroyed for an unexplained reason, so they came to earth to settle — but crashed their spaceship during entry, and sunk to the bottom of the ocean. They then spent so much time on Earth that they even forgot their origins.
• It's hinted that Kabapu and Il Palazzo of Excel♡Saga (and possibly Excel herself and the Ropponmatsu), are connected to a lost civilization called Solaria, which may well be an example of this. Particularly as Tenmangu Shiouji didn't believe their technology could be created on Earth. And if it can't be created on Earth that kind of leaves only one option...
  • Shiouji's son Goujo actually states this Trope by name while ridiculing the idea that Kabapu's claims as to his origins are true.
• In the manga Paradise on the Sand, the ruling class of the unnamed pseudo-Middle Eastern country in which the story is set believe that they once lived in Heaven with the gods, but were eventually banished, and told that if they kept their blood pure they would one day be allowed to return. In addition, the enigmatic character Raisa is heavily hinted to be a goddess come to check up on them. They came from the heavens, all right — in a spaceship. And Raisa is indeed there to check up on them, but a goddess she's not (though she's sufficiently advanced to be mistaken for one). The blood purity thing was all their invention, though.
• In Spriggan, one of Yu Ominae's missions in Mexico reveals that the gods the Mexicans worship in the old days are actually ancient astronauts. With some exceptions.
  • Not to forget an early chapter/in the OVA movie in which ARCAM scientists discover Noah's ark an ancient space ship which has the ability to directly control the Earth's atmosphere and is heavily implied to be the source of all life that has, is and will be on Earth.
• In Shaman King aliens are mentioned to have visited Earth on numerous occasions, each time leaving behind signs of their presence. In particular, Rutherfor's guardian ghost Grey Saucer is the spirit of a nameless traditional-looking alien who crash-landed on Earth many years before the events of the series and befriended the Patch Tribe, gifting them with the technology used in the Shaman Fights commonly known as "traditional Patch Art".
• In One Piece this appears as well (to some extent). Although never explained in detail a number of technologically advanced winged humanoids lived on the Moon (the Skypieans, Shandians and Bilkan), when resources ran out they departed the moon. Upon initially seeing them they were mistaken for angels, and their shadows (from those that lived in the clouds) were often mistaken by sailors as being the silhouettes of giants.
• The Protoculture of Macross are presented as such in the prequel Macross Zero, when it's revealed they have influenced the culture of the people of Mayan Island (it's also hinted they interbred with them) so they would be able to activate an artifact (the "Bird Human") that would either bomb mankind back into stone age if they reached space before renouncing war or provide Protoculture technology if they did renounce war. Humans being humans and the Anti-UN having just bombed Mayan Island before it was activated, the Bird Human immediately arms its Wave-Motion Gun.
  • Come Macross Delta, it's revealed that the Protoculture had a presence on the homeworlds of several other species, including, but not limited to, the natives of the Brisingr Globular Cluster, leaving behind several powerful artifacts that drive much of the plot.
• In Higurashi: When They Cry this is the explanation given for Oyashiro-Sama and the virus causing Hinamizawa Syndrome during Tsumihoroboshi. However it's not quite accurate.
• The Nitro's from Toriko are heavily implied as being this, if the hieroglyphics in the Gourmet Palace are a given.
• Kyubey aka The Incubators from Puella Magi Madoka Magica invokes this as the result of their intervention, with human civilization, science and progress as the result of the sacrifice of Magical Girls and various historical figures such as Cleopatra herself making a Deal with the Devil with them. He even comments that if Madoka wishes that they never existed, then humans would "still be living naked in caves."
• The Life Fibers from Kill la Kill are responsible for mankind evolving to the point that they wore clothing, manipulating civilizations for their harvest of energy.
• Sgt. Frog does this a few times:
  • The Kappa that ghost girl Omiyo befriended long ago was really a Keronian scout wearing a helmet that made his head look like a kappa's.
  • Played for Laughs in one episode of the anime, which revealed that various sites attributed to ancient aliens were actually amusement park attractions: Stonehenge is a giant solar-powered stove, Macchu Picchu was the site of a giant roller coaster, the Pyramid of Giza is a haunted house, and the Moai heads of Easter Island are a giant game of whack-a-mole.
  • The manga had a more serious interpretation of Easter Island, where the Moai were there to seal away evil spirits (read: ancient alien invaders).
• In the H-manga Dulce Report, the aliens, codenamed "Angels", have been interacting with humanity for over six thousand years in order to create Human-Angel hybrids for an unknown reason. The fact that much of the lore includes real-life conspiracies such as the Dulce Air Force Base and even Alburquian businessman Paul Bennewitz was used, though changed into a British geneticist to fit the story, is what makes the story a great Porn with Plot manga.

Comic Books

• The DCU:
  • In the DC Universe, White Martians visited Earth in early prehistoric times, and sabotaged the human genome to weaken the metagene so it would only manifest one of its many potential powers per person, and only rarely and in times of duress. Had they not done so, all humans would possess uniform high-tier superpowers like the Kryptonians, Daxamites, or the Martians themselves.
  • In the post Infinite Crisis retcon, the Daxamite race, an off-shoot of the more famous Kryptonian race with the ability to interbreed with human, has been shown sending their explorer on Earth, in ancient times. Due to Daxamites and Kryptonians gaining Superman-like powers from a yellow sun, they gave themselves a strict no sex rule. That didn't prevent them from passing down the history of the Gods of the Mesoamerican pantheon and while some of their offspring lead humanity to formulate legends about demigods and other mythical heroes, a particular Daxamite, Bal Gand, escaped back on Daxam, programming her ship to carry her mixed-race future son back to Earth if he was ever ostracized for that.
  • In Grant Morrison's Seven Soldiers of Victory (2005) and Final Crisis, the New Gods are revealed to have visited Earth during the prehistoric era, influencing human culture and providing humans with technology.
  • Wonder Woman:
    • Wonder Woman (1942): Osira is an Ancient Alien Astronaut who landed in Ancient Egypt and claims to have been worshiped and responsible for the pyramids. Her story is however rather self serving and the only thing actually known about her interactions with the Ancient Egyptians is that they bound and imprisoned her in a multilayered seal when they found they couldn't kill her.
    • Wonder Woman (1987): Briefly posits that the Lansinarians are responsible for the Ancient Egyptian's pyramids, mostly as a way to excuse the fact that the Lansinarians look like Egypitan gods as humanoids with animal heads and as a nod to Osira's pre-Crisis background. This pretty much never comes up again.
  • In the DC Comics Bombshells universe, Hawkgirl is introduced as a strong opponent of these theories, holding the position that they're the result of racist disbelief in the abilities of non-white cultures. Then it turns out that the Thanagarians did invade Earth earlier in its history, that she's descended from them, and that her girlfriend's "magical" abilities are powered by ancient Thanagarian technology. Awkward.
• Marvel Universe:
  • A borderline example: the Sphinx was a time machine created by Rama-Tut, a human time traveler from an alternate timeline's future. A 1971 The Incredible Hulk story had the Sphinx being left behind by aliens as a weapon.
  • Inverted by X-Men villain Apocalypse. Being an immortal mutant shapeshifter with access to alien technology, he would claim to be various deities in order to more thoroughly dominate whatever group of people he was subjugating at the time.
  • The Eternals are a super-powered, immortal human-offshoot race created by ancient astronauts, and were often mistaken for gods. Their Always Chaotic Evil counterparts, the hideously mutated Deviants, were the inspiration for many mythical monsters and demons.
  • Warren Ellis used a similar idea in The Mighty Thor, suggesting that Asgardians are simply technologically-advanced aliens whom had been mistaken for deities by primitive humans. It was left ambiguous as to whether the Asgardians had influenced early viking culture, or vice versa. The idea was abandoned by subsequent writers, who opted to continue portraying the Asgardians as explicitly supernatural entities. Though whether this distinction is actually important is debatable; the Asgardians clearly are advanced people who came from another planet to Earth in the past and interacted with more primitive humans.
  • Although literal Chinese dragons do exist in the Marvel Universe (thanks to Iron Fist's backstory), Marvel's most well-known ancient "dragon" is a giant alien named Fin Fang Foom.
  • A more straightforward example is the Earth X trilogy, which states that all the "Gods" in the Marvel U (the Asgardians, Olympians, Egyptians, etc.) are examples who were shaped into their current forms by humans' beliefs.
• Bec and Kawl from 2000 AD featured a story about a race of aliens resembling traffic cones that apparently forced all the ancient humans into slavery for the sole purpose of building conical monuments to them. Humans eventually rebelled and after the aliens fled the planet, the humans developed basic geometry and modified the alien monuments to show this (explaining the likes of the Egyptian and Aztec pyramids and Stonehenge). Presently, the aliens are hiding amongst us disguised as, you guessed it, traffic cones.
• The Authority story arc "Outer Dark" by Warren Ellis is about a giant triangular space god who created the Earth coming back to sterilize it of human life could be considered a Lovecraftian-idiot-god chaotic evil version of this. The alien "god" could also be considered a Big Dumb Object.
• Captain Gravity: As shown in Flashbacks during Professor Goethals' narration of the history of the Itza Maya, aliens are shown to have visited them in ancient times. As a result, they were viewed as gods by the Itza Maya, and helped them build their society with the power of Element 115.
• In the Elfquest series, the elves' psychic space alien ancestors came to the World of Two Moons because they discerned signs of their own kind in native humans' art and culture, and wondered if their species had been there in the past. This became a self-fulfilling prophecy.
• Gods from Outer Space was a 1970's Polish adaptation of von Däniken's theories into a series of graphic novels.
• Paperinik New Adventures has a few examples. In order of appearance, we have:
  • The Evronians, of all aliens, having first visited Earth about ten thousands years in the past and visiting multiple times until we became suitable for conquest.
  • In Urk's parallel universe an unspecified alien race, strongly hinted to be the Evronians of that universe, visited Earth at some point in the distant past, giving advanced and eco-friendly technologies to the populations of the American continent and teaching them how to live in peace while still being able to defend themselves by invasion of the Vikings (who, by the time they discover America, have advanced to technological levels slightly superior to those of late 20th century Earth by themselves).
  • Back when the dinosaurs roamed the planet, Earth became the battlefield of two advanced alien races, now apparently extinct. One of them, forced to leave in the face of an invasion with overwhelming strength, left around a Mind Control device that brainwashed the dinosaurs into attacking their enemies and, after surviving under Duckburg for over 65 million years brainwashed Rupert into attacking Paperinik, as his costume happens to resemble the uniforms of the aliens.
  • It's hinted that both the Xerbians and the Coronans have visited Earth at multiple points in the past, as shown when the Xerbian refugee starship Antra set course specifically to Earth to warn them about the Evronian threat (not knowing there was already an Evronian invasion force there and they had an Evronian infiltrator on board) and Everett Ducklair choosing Earth as his refuge.
• In Pocket God issue 3, the tribe finds a temple with hieroglyphics describing a ufo and aliens. Turns out they were the ones who put a laser gun on the shark that keeps chasing them.
• A Sam & Max: Freelance Police short had them going into the past and thwarting Egyptian aliens. Like everything else in the series, purely played for laughs.
• Inverted in Supreme Power; whilst the alien Zarda did show up during the age of Ancient Grome, the Greco-Roman pantheon was well-established before she arrived and she imprinted on it, to the point she now believes herself to be a Physical God rather than a super-powered alien.
• The Tintin story Flight 714 takes place on an island regularly visited by Ancient Astronauts and their "initiates" right up to the present day.
• In Wild CATS Wild Storm, it's implied that the immortal alien Kherubim and body-snatching Daemonites (note the names) are the inspirations for many Earth legends.
• In Tragg and the Sky Gods, the alien Yargonians visited a tribe of Neanderthals and were regarded by them as gods. A generation later, the Yargonians return, but this time as conquerors.
• A Gold Key issue of Scooby-Doo has the gang flown to Mexico on the dime of a museum to retrieve an artifact stolen from them of a ship of an ancient astronaut. The perps behind it are actually after a submerged cache of gold coins.

Comic Strips

• Parodied in a Brewster Rockit: Space Guy! sequence showing ancient drawings depicting events such as:
  1) Alien arrives and is worshiped as a god by primitive humans
  2) Alien explains to primitive humans that he is not a god but a being like themselves
  3) Primitive humans pelt alien with stones for not believing in their god.

Fanfiction

• Child of the Storm has Asgardians as being this — they started out over a million years ago as Sufficiently Advanced Aliens whose main interest in Earth was strategic in their war with Surtur, with a degree of curiosity related to the potential that the Eternals and Deviants demonstrated that humanity's ancestors possessed. After the creation of Yggdrasil, a cosmic prison for Surtur (the original Dark Phoenix), they became gods, and retained an interest in Earth, protecting it from outside interference. However, when they tried to help out humanity in earnest, c. 20,000 years before the present, it resulted in the Atlantean Empire, a fusion of Marvel's Atlantis and Stargate's Ancients... which worked very well right up until it didn't, and the Atlanteans destroyed themselves, and nearly took the universe with them.
• In Divine Blood, the Demons and Gods are basically previous evolutions of sentience and then immortality that developed on Earth and then left to extradimensional safe havens to avoid some extinction level events. Frequent interaction with humanity has caused them more or less to assimilate to human culture to the point where even the basically down to Earth human-friendly set think of Demon and God as their species name.
• In Equestria: A History Revealed, aliens apparently exist in the world of Equestria, and were behind the creation of Discord. Of course, given our loopy narrator and her lack of evidence on this matter, she may just be making it up.
• It turns out that Krypton had sent a failed sleeper ship to prehistoric Earth in The Last Daughter, much like in Man of Steel.
• In "The Gods in the Stars" humanity was this to ponies.
• Sonic X: Dark Chaos: Humans were descended from Angels who originally colonized Earth as an outpost on the Federation border. They were nearly wiped out by a Demon attack, which caused them to lose their technology and regress. Some of them switched sides and worshiped their Demon invaders; many older pagan religions were based on Maledict.
• A paranoia-inducing Discussed Trope in Day of the Falcon, a Stargate-verse/Tomb Raider Crossover; whether or not Ancient Astronauts exist in a given universe, only a fringe archaeologist would even suggest the possibility, as No True Archaeologist would abide the blow to their humanocentric worldview.
  Humans are smart. When you say we need aliens to tell us how to build, how to paint, how to water crops, you are saying our ancestors are children. Or maybe you are saying Egyptians are children, are idiots, who need outsiders to tell them how to feed themselves. And that is why I am so angry about these things like this you show me and the fools who want to see flying saucers and spacemen in helmets in everywhere where there is serious archaeology being done. My life's work is to show the past, our Egyptian past, the past of all of us. It is to be proud to be a human being. These aliens…they are just distraction.
• Hatchling Quest reveals that the Chozo have visited Earth Bet from as early as Ancient Egypt.
• Inverted in I Still Haven't Found What I'm Looking For. Harry Potter notes that for thousands of years, the galaxy has been using things that were invented on Earth much later. The galaxy at large uses a calendar almost identical to the Gregorian Calendar, on top of using the metric system, speaking English, and using an alphabet eerily similar to the English alphabet. Lastly, things done with the Force seem like half-baked magic. Since Harry has mostly proven that the Veil of Death is not only a portal to a galaxy far, far away, but is also non-linear in terms of both time and space, he theorizes that someone or multiple someones ventured through the Veil and ended up influencing the galaxy at large.
• Much like the canon series mentioned above, the Puella Magi Madoka Magica fanfic A History of Magic states that the Incubators intervened with history when necessary in order to create more Puella Magi, to the point of instigating wars behind the scenes and having Alice in Wonderland published to get girls to dream when fewer girls were contracting. However, they're only supposed to intervene when it's necessary to do so and no more, which is why Kyubey was questioned on why he aided the Manhattan Project, which wouldn't help the Incubators at all. When Kyubey stated his belief that if he hadn't, all the powers trying to build atomic bombs would succeed at the same time and drop them, causing a global annihilation that would cost the Incubators its current source of energy, the Directors calculated he was right, and commended him on his forward thinking.
• The Last Son:
  • The Kree visited Earth over a thousand years ago and were responsible for creating the Inhumans and the intelligent gorillas of Gorilla City. S.H.I.E.L.D salvaged a Kree vessel and used their tech to empower Carol Danvers, turning her into Ms. Marvel.
  • A Kryptonian explorer named Kon-Lir was stranded on Earth in the 16th century, when he tried to force the Skrulls and Kree to vacate the planet. He made an enemy out of Selene, as he refused to worship her as a goddess and encouraged others to do the same, causing her to develop a great hatred for the Kryptonian race as a whole. He also made a first contact mishap with the Atlanteans (due to being unable to control the powers under a yellow sun) which caused Atlanteans to fear and refer to the Kryptonians as the "Travelers". Lastly, believing that he doesn't have a chance of returning to Krypton, he decided to settle down and subsequently married a human woman, and inadvertently becoming the ancestor of Alison Blaire. His ship was eventually found and salvaged by Superman, who repaired and upgraded it for his own use.
• Becoming a True Invader: Dib is surprised to find Egyptian hieroglyphics on Heboad, suggesting a visitation to Earth in the past. Zim states that advanced species visiting primitive planets isn't unheard of.
• Bumblebee in A Girl and Her Bike is surprised to find out that, while the symbols used are different, the Vytalese characters all have the same name as their corresponding character in the Cybertronian alphabet. His best guess as to why that is is that another Autobot woke up when the language was being developed.
• Discussed in A Is A, as Fareeha and Daniel try to find potential allies against the Goa'uld. Fareeha states that after coming from a universe where ancient aliens is used to essentially rob ancient Egypt of its achievements, facing a universe where there were ancient aliens is somewhat grating.

Films — Animation

• The 1997 Australian animated film Go To Hell! (1997) by Ray Nowland has a lot of fun with this trope: Corrupt Corporate Executive G.D. builds a space ark to escape the destruction of his planet, planning to set himself up on an Insignificant Little Blue Planet in a God Guise. But he's opposed by his rebellious teenage son Red (who bears an unusual resemblance to Satan) who gives humanity a helping hand.
• Spoofed in Ice Age when the prehistoric main characters pass a giant Flying Saucer frozen in an ice cave. Bonus points are awarded for having the Neanderthal baby flash the Vulcan salute at it.

Films — Live-Action

• The Fourth Kind features "evidence" of Aliens speaking Ancient Sumerian, implying that they interacted with ancient Sumerians, possibly teaching them their native tongue.
• The Fifth Element has the Mondoshawan, a race of friendly aliens that visited the Earth "before time was time", with a succession of human priests being established to protect the Fifth Element within a temple in Egypt. They show up in the 1914 prologue to take the Fifth Element away before World War 1 breaks out and promise to return it in The Future when the Great Evil will threaten the Earth.
• Stargate: Ra was an extraterrestrial interplanetary explorer. He also built the Pyramids to be somd landing platforms for his spaceship, while possessing a human body to serve as his host (humans, it seems, are easily repaired by his medicine). Other humans were enslaved to mine the mineral used for his technology.
• Indiana Jones and the Kingdom of the Crystal Skull. The titular crystal skull form a small part of an entire crystal skeleton, which belonged to a stereotypical "grey" alien interdimensional being that had advanced human civilization throughout the ages (it split into 13 individuals to dilute its powers in order to safely communicate with the locals). As it turns out, knowledge was their treasure. Their treasure was knowledge. When a KGB Agent tried to have all this knowledge downloaded into her brain...it was too much for the human physique and she was incinerated in the process.
• Mission to Mars reveals the origin and purpose of the mysterious face on Mars and that all life on Earth was seeded by ancient astronauts fleeing a dying Mars. The fact that later, higher-res photos proved in real life that the Mars Face doesn't actually look anything like a face slightly ruins the effect. It's also explained with a line from Luke to the effect that the face, having been buried in dirt in the intervening millennia since its construction, looks somewhat different than its architects intended. Indeed, when the security system activates, one of the side effects is a nice dusting (one wonders why the aliens wouldn't have taken erosion and weather patterns into account when building it, but there you go).
• Pacific Rim heavily implies that dinosaurs were indeed a first attempt of an invasion, which didn't work because the atmosphere, at the time, was not adapt for the invading forces; humans, heavily polluting it, fixed that problem for them.
• AVP: Alien vs. Predator provides a rationale for why the visitors were regarded as godlike beings but still only influenced humanity in the pyramid-building direction: Earth was (and still is) a rite-of-passage hunting ground, only visited once every century in designated sites built for the purpose. Occasionally, things got out of hand and the visitors had to resort to continent-blasting weapons. For previous uses of this in the Predator canon, don't forget Predator 2, and the antique flintlock from the 1600's, kept as a trophy and given as a gift.
• The indirect Alien prequel Prometheus deals with the mystery of the space jockey, revealing that it is a suit worn by giant humanoid alien beings known as "the Engineers". The movie opens with one such being on earth, drinking a potion and disintegrating in strands of DNA, forming the basis for all life on earth.
• Transformers: Revenge of The Fallen has the Seven Primes, who came to northern Africa about 19,000 years ago, The Fallen built the Solar Harvester, got into a war with his fellow Primes for possession of the Matrix. He wanted to kill all humans and get loads of Energon while at it. His brothers hid the Matrix of Leadership in a tomb made of their own bodies, a tomb the Fallen's Decepticon Seekers cannot find. Seymour Simons believes various ancient archeological sites has evidence of Transformers visiting due to cybergylphs. The Ruins of Petra turns out to be the Primes tomb and the Pyramid of Giza as the Solar Harvester in disguise.
• Implied in 10,000 BC. The slaves say that the God of the Pyramid came down from the stars. Others say he's from Atlantis, so we get two common flavors of this trope offered at once.
• Used in 2001: A Space Odyssey, when early hominids discovers The Monolith. See the "Literature" section.
• In Cocoon, Atlantis was the Antareans' first base on Earth.
  Walter: Everyone else said, "use the North Pole," and I said, "no, too cold." Sinking never occurred to me.
• In Thor, the character Darcy speculates that Thor and the other Asgardians are not actual Gods, but rather extra-dimensional aliens whom early humans mistook for supernatural deities since, well, they have Nigh-Invulnerability and technology that looks like magic to human eyes. The implication is that early Scandinavians patterned their society after the Asgardians, thus explaining the similarities between the two cultures.
  • Thor: Love and Thunder reveals that multiple "Gods" (including Zeus) are actually aliens, presumably they too visited Earth and influenced early cultures.
• In Star Trek Into Darkness, the crew of the Enterprise is likely to become Ancient Astronauts to at least one tribe on the primitive planet of Nibiru after violating the Prime Directive.
• In Star Trek Beyond, the Big Bad reveals to have found the remains of an advanced, space-faring civilization referred to as the "Ancient Ones" while stranded on Altamid, using their cache of technology for his own purposes, raiding passing ships to capture and drain their crews to extend his life while searching for the missing half of the Abronath, a dangerous Bio Weapon engineered by the Ancient Ones.
• DC Extended Universe:
  • In Man of Steel, explorers from the Kryptonian space program crash-landed on Earth sometime during the Stone Age. The prequel comic implies that their spacecraft's arrival showed up in the mythologies of some early humans. Jor-El also mentions how Kryptonians have ventured in space for hundreds of thousands of years.
    • The digital comic book Man of Steel Prequel reveals that the ship that crash-landed on Earth had only one survivor, Kara Zor-El.
  • In Zack Snyder's Justice League, Diana/Wonder Woman goes in a crypt beneath a Greek temple and finds a fresco depicting Darkseid. It dates back to the last invasion of Earth by the New Gods of Apokolips thousands of years prior.
• In Hangar 18, the scientists studying the crashed UFO and the dead Human Aliens in it determine that others like them came to Earth long ago. In fact, modern humans are partly descended from those who took human women as mates.
• Wadatuzin from Ultra Q The Movie: Legend of the Stars is an alien who arrived on Earth several millenia ago, who ends up being unable to reawaken her spaceship and amazed with the beauty of nature, where she then started a cult to teach the then-primitive humans to preserve the environment. She was worshiped as a wrathful goddess for centuries to come until humans have advanced sufficiently and gradually forgot about her existence.
• In Godzilla (2014), all those sea dragons in medieval texts are in fact Godzilla, as the opening credits show, and Godzilla was written about dating back to prehistoric cave paintings. It's a similar story with the other Titans being the source material for mythological gods and monsters all over the world, but King Ghidorah takes the cake as revealed in Godzilla: King of the Monsters (2019) because he's an actual alien that landed on the planet during the last Age of the Titans.
• In Jupiter Ascending, the alien dynasties that seeded Earth millennia ago inspired many of humanity's myths about vampires and dragons (one of the races that work for Balem even looks like smaller dragons) and possibly even deities. Humanity isn't even native to Earth, having actually evolved on a planet called Ourus, and Earth was "seeded" by Abrasax Industries roughly one hundred thousand years ago.
• X-Men: Apocalypse: En Sabah Nur and the Four Horsemen are debated by Agent Moira MacTaggert and Alex Summers. Did he take the idea from the Bible... or did the Bible take the idea from him?
• In John Carter, it's implied that the Therns have been visiting Earth/Jassoom for millennia, given the clearly Barsoomian symbols John's archaeological expeditions find. Also, the Big Bad has been on Earth enough times lately to recognize John's Southern accent.
• In Iron Sky: The Coming Race, it's revealed that the Vril came to Earth in prehistoric times, fleeing from an unspecified cataclysm, and decided to stay. One of the two brothers leading the Vril is a scientist (he would later adopt the name Wolfgang Kortzfleisch and become the Moon Fuhrer after his brother Adolf Hitler fled underground), who starts performing experiments on local lifeforms. Unwilling to wait for evolution to take its natural course, he uplifts two monkeys (you can guess their names) into the first humans.
• In Save the Green Planet!, the executive gives a speech claiming humans were created by the aliens based on their DNA. This narrative includes many classic features of the trope, including the creation of cavemen and a Shout-Out to the beginning of 2001: A Space Odyssey. It turns out that he was correct, and the alien precursors actually look like people from ancient Chinese/Buddhist art.
• In Frankenstein Island, the island was the landing place of aliens who were the ancestors of the Nubile Savage Amazons. Dr. Frankenstein chose the island as his base of operations so he could access their technology.
• Discussed in Horse Girl. Darren brings up the conspiracy theory that aliens built the pyramids and kickstarted human civilization, which Sarah finds fascinating and immediately believes after hearing it.
• Discussed in Killer Klowns from Outer Space by Mike. He figures that the titular aliens paid Earth a visit hundreds of years ago and that everything humanity knows about clowns comes from that supposed outing. While this theory is never proven or discredited, it may explain why people in this particular universe have grown to fear and despise clowns.
• The science editor from God Told Me To once published an article about how God might have been an ancient astronaut.
• Discussed in the "Al TV" segment from The Compleat Al, as "Weird Al" Yankovic explains how the greatest rock songs were originally given to humans by ancient aliens.
• Eternals: The Eternals were sent to Earth to protect life from the Deviants, and living throughout its history, complete with some influence in human evolution.

Literature

• In the Age of Fire series, the wizard Anklemere, as well as the trolls, are implied to have been this. And the Lavadome is apparently the spaceship that brought them. Being a fantasy series, however, such terminology isn't used, nor is it ever confirmed.
• Explored in Alterien.
  • The Shanda'ryn, a race of aliens closely modeled after The Greys, appeared in various points of human history. Humans sometimes mistook them for figures out of their belief systems. They were also present during the time the Pyramids of Egypt were originally built, a time that predates the known Kemetic (Egyptian) Dynasties.
  • The Alteriens themselves also assumed this role with their many voyages to Earth's past.
• Subverted in the Animorphs books. Earth has been visited by aliens countless times throughout history, but each time it is hinted that they took a hand in humanity's development it is quickly explained that that is not the case. Despite all the aliens who seem inexplicably drawn to our blue planet, all the credit (and the blame) of our history goes to us.
  • Two alien species, the Nesk and the Mercora, attempted to settle the earth sixty-five million years ago. When the Nesk realized that they could not have the world to themselves they redirected an asteroid to impact the planet. This wiped out the dinosaurs and removed all evidence of both societies long before humanity evolved. Though the Nesk may have evolved into ants.
  • The Chee are a race of ageless, powerful androids living disguised among humanity after they came to the Earth thousands of years ago. They make it a point to not amass any power or control over human society, and their involvement in big events is always purely tangential. Erek King once stated that he helped build the pyramids, but then explains that he was a slave who helped haul the bricks. A few millennia later he was an assistant to Beethoven, cut and styled Catherine the Great's hair, and coined the phrase "New Deal" at a poker game at the White House in the 1930s (as a butler not an official). Then there was Mr. King, Erek's 'father', who suggested pasteurization to Louis Pasteur. Another Chee is currently living as a homeless woman, but in a previous life was a very successful (unnamed) actress.
  • The Ellimist plays it straight... just not with humans. He assisted the Hell out of the galaxy, and it's heavily implied the Andalites were included (though how much he helped them while his organic proxy was living with them is unclear).
  • The Skrit Na have been known to abduct sapient and nonsapient beings for medical experiments that makes sense only to them. Notable in that they are so ancient that they were an advanced space-faring race far before the Ellimist attained any semblance of godhood.
• Artemis Fowl: The reason why Artemis can translate the fairy language so easily is that it is similar to Ancient Egyptian, and Artemis comments this is because the Egyptians borrowed it from the fairies.
• Averted in the 'insulting humans' sense in an Isaac Asimov short story. Spaceships are forbidden to trade with cultures that don't have anything to offer. A quick scan of the planet convinces most of the crew that humans are just a simple hunter-gatherer society, but the trader's instinct says that they do have something to offer. Played straight in that the traders do help them, giving them the wheel and tools, but the traders gain something by learning to use caricature and sketches from the human's ancient art. Sketches have an advantage of highlighting characteristics that are important, and getting rid of information that is unimportant. The space-faring culture had forgot (or never had) times without photo-realistic holograms.
• In Blood of the Heroes, time travelers discover that the Indo-European deities are actually aliens called the Teloi, who engineered modern humans out of Homo erectus when they arrived.
• Childhood's End invokes this, but the myths aren't from memory, but rather precognitive visions of the aliens.
• Inverted in Dragon's Egg, in which mankind inadvertently jumpstarts a civilization: the barbaric Cheela, seeing a new, wandering star in the sky (an orbiting human vessel), mistake it for a god and develop astronomy and writing in order to follow it. This starts their technological development, and they eventually make First Contact. As a bonus, since the Cheela's Bizarre Alien Biology operates on nuclear reaction time scales, rather than chemical, they manage to do it in days.
• Louise Searl's short story collection The Dream Eaters and Other Stories features this idea in the story Lightbringer.
• Dream Park: The trope-savvy Game Masters of Dream Park use this as a premise for their live-action adventure tournament in The California Voodoo Game.
• This exists in a modified form in the Dune universe. That universe is Absent Aliens, but the same trope happens with more advanced civilizations of humans doing it to less advanced societies. This is most common with the Bene Gesserit Missionaria Protectiva.
• One of the earliest examples of this trope (perhaps the earliest) was in Edison's Conquest of Mars, an unauthorized sequel to The War of the Worlds (1898), in which Thomas Edison invents a spaceship and launches a counterattack against the Martians. Here, it's revealed that the Martians built the Pyramids and the Sphinx.
• The Empire from the Ashes series has all of Earth's humanity be descended from the marooned crew of a spaceship after a partially successful mutiny (the spaceship in question is in fact disguised as the moon).
• In the Galactic Marines series, this happened with three different alien species. First the cybernetic or mechanical Builders who tinkered with the ancient human genome to create Homo erectus, then the Ahn who used human slaves in ancient Mesopotamia, and finally a third species who helped humans get back on their feet after the Ahn were wiped out. Some of the conflict on Earth arises from the so-called "Ancient Astronaut" cults, who claim that aliens were benevolent gods, who will eventually return and solve all of the world's problems.
• In the Giants Series, humanity was accidentally uplifted by aliens from Minerva (which was the fifth planet in the solar system before it was blown up).
• In Junction Point, it's revealed that the tianlong visited Earth over a hundred thousand years ago and encountered the Neanderthals. When they heard of their homeworld's destruction, they returned to help the sole surviving colony, but the thought of how fragile life in the universe is convinces them to later come back to Earth and set up a colony of humans and Neanderthals on another world. Unlike other examples, however, the tianlong didn't actually influence civilization on Earth, except perhaps for the legend of dragons.
• Larry Niven did this a few times in his Known Space universe:
  • The Pak actually were the ancestors of humans as part of a Lost Colony that failed due to a lack of Thallium Oxide in the soil, resulting in a race that failed to reach the final stage of the Pak life cycle.
  • Prior to the Pak, the Thrintun were the source of the beginnings of life on Earth when they seeded the world as a food source and then lost contact with it, preventing them from weeding out mutations in the yeast strain they used to seed the planet.
  • A non-Niven story set in Niven's world mentions an abortive Kzin visit resulting in myths about particularly nasty tigers.
• The Lives of Tao has this as the core of its premise: an ancient race of Energy Beings crash landed on Earth millions of years ago (killing the dinosaurs and kick starting the ice ages in the process), symbiotically possessing various creatures to stay alive while gradually furthering the evolution of life until early humans came along and manipulating our development from there. Almost everything in Earth's history is the result of Quasing manipulation.
• The Ollan refugees in Aleksandr Zarevin's Lonely Gods of the Universe are a small (less than a dozen) group of redhaired teenagers, their professor, and a security guard sent to a habitable planet with primitive inhabitants using an experimental teleporter. They call this pristine world Pearl and establish a compound on an island. They plant the seeds of a salad plant known as ambrosia from Oll, and the plant grows overnight. They eat it, grow sick, and collapse. A day later they wake up youthful (even the old professor), healthy, and immortal (well, Healing Factor and agelessness). They end up ruling over the dark-haired primitives on the island, with male Ollans impregnating many local females, resulting in varied hair colors. The locals build them a palace on top of a large hill at the center of the island. The Ollans call it Oll-lympus. The island they call in honor of their home country Atl back on Oll — Atl-antis. Long story short, a vision warns them of a comet about to strike the sea and sink the island. A number of the locals and the Ollans manage to get away to the mainland. They survive to the present day and secretly use their amassed fortune to finance research into re-creating their teleportation device (which was left behind on Oll, and its use resulted in a nuclear war, making them the last Ollans).
  • For bonus points, the name of the Ollan security guard, who became the military leader of Atl-antis, training locals in hand-to-hand combat and tactics, as well as having them build ships and weapons for conquest of the mainland, is Mars Ares.
• In The Long Earth, Lobsang speculates that a great deal of human mythology originated from misinterpreted encounters with trolls and elves, who in this setting are apelike creatures with the natural ability to "step" between parallel Earths.
• In A Lord from Planet Earth, various Human Aliens have been visiting Earth for centuries thanks to teleportation technology. They couldn't visit en masse due to Earth's hyperspace coordinates not being provided by the Temples (one exists on every homeworld except Earth), but teleportation works differently. This has resulted in myths about strange visitors and creatures like vampires (that would be the Palians, who drink blood, have great physical strength, and are damaged by our yellow dwarf's spectrum). Then inverted, as it turns out that all known races in the galaxy were created by 22nd century humans using Time Travel, who then left behind fake clues about a race of Precursors called Seeders, all in the effort to create an army to fight in an intergalactic war.
• H. P. Lovecraft:
  • This trope was popularized in At the Mountains of Madness, which reveals that ancient aliens who lived on Earth before humanity inspired the ancient legends that Lovecraft hinted at in earlier, more fantastic stories...
  • The Great Race of Yith in "The Shadow Out of Time" is another example, and Cthulhu and the other Great Old Ones are alien (possibly extradimensional) beings that came to Earth eons ago. However, they aren't just worshiped as gods, they actually kind of are. What else would you call an immortal, nigh-omnipotent being that can bring about the end of the world on a whim?
  • As part of the distinctly bleak worldview conveyed in his stories, however, Lovecraft put a notable spin on this trope: his aliens and space-gods are not interested in guiding humanity's development, nor (with a few exceptions, such as Dagon) in enslaving or corrupting us. They rarely give us a second thought, as we were basically ants in comparison (perhaps even less).
• Terry Pratchett used this for his Nomes Trilogy; humanity's stories about "the little people" are actually due to contact many centuries ago with a species of tiny Human Aliens, a group of whom stranded themselves on the planet by accident. They used to directly interfere, in an effort to coax humans towards creating the technology they needed to contact their mothership, but failed due to the Time Dissonance — they basically devolved to the point where they both lost the ability to communicate and all memory of where they came from.
• Norby And The Lost Princess: It was briefly mentioned in the previous book, but this is when the background of the Others coming to Earth and taking a colony of humans with them to a different planet is explained. The Others took the community to a planet that they named Izz, but left no signs of themselves on Earth.
• The Northwest Smith stories contain a variation on this theme. It is implied that a prehistoric civilization of humans mastered spaceflight and brought back tales of the creatures they encountered on other worlds, which became the basis of later legends.
• Out of the Silent Planet:
  • There's an inversion here. C. S. Lewis' Author Avatar translates a manuscript by the 12th century Platonist Bernardus Silvestris, describing a voyage through the heavens and mentioning Oyarses, a tutelary spirit assigned to a planet. Said author avatar seeks translation help from Dr. Ransom — who had himself recently voyaged to Mars and spoken with Oyarsa, and thus recognizes Silvetris' account as a true one. As for Oyarsa, he's an Energy Being, an angel, and a god.
  • Maleldil the Young, leader of the inter-planetary eldils, infiltrated Earth after the eldil assigned to protect it went rogue and silenced all communication with the rest of the Solar System. Maleldil gave humanity the means to overcome the corruption of the bent eldil by becoming one of them, after which He ascended to Jupiter.
• In the German sci-fi series Perry Rhodan, this happens a lot. The sheer amount of ancient astronauts that have visited Earth in the Perry Rhodan Universe is perhaps better understood if one realizes that Clark Darlton, one of the creators of the series, was actually a friend of Erich von Däniken and the two wrote a sci-fi novel together about the topic of ancient astronauts. Atlan the Arkonide (more than 10,000 years old and immortal due to some Applied Phlebotinum granted to him by a Sufficiently Advanced Alien Energy Being) is supposed to be responsible for some of the oldest human myths, like the Epic of Gilgamesh. In one of the spin-off novels, we can even see Atlan acting like a god in front of primitive humans. Atlan's people the Arkonides build their first colony on the famous Atlantide landmass (to state the obvious, it's named after him).
• Subverted in The Roswell Conspiracy by Boyd Morrison. It's implied that the Nazca lines are connected to the UFO that crashed at Roswell. It turns out that Nazca was built to show their gods where a highly deadly radioactive meteor remnant which they believed belong to their gods was hidden. And the Roswell UFO was an experimental Russian aircraft powered by this same radioactive element recovered from the meteor which created the Tunguska blast site, and the Russians want more of it so they go looking for the Nazca sample.
• The X-Files novel Ruins has Agents Mulder and Scully venturing to a recently uncovered Mayan ruin in Mexico to search for a missing archaeological team. Once they arrive there, Mulder discovers a spaceship underneath the structure, and comes to the conclusion that it belongs to an alien who was stranded on Earth 1000 years ago, whose presence lead to the stories about the mythological Kukulkan.
• The Saga of the Exiles by Julian May has humans being the descendants of ancient astronauts from another galaxy who interbred with time travelling humans from the near future from our point of view. Most names for the aliens and locations are corrupted from Celtic, especially Irish, mythology. It's implied that the alien/human civilisation a few million years in the past is somehow responsible for the eventual occurrence of homo sapiens and Irish myths, although it's never explained how this was supposed to work. Also a good example of A Mythology Is True.
• In The Science Of Discworld, a band of early hominids is saved from a leopard, then introduced to the concept of "fire," by a wise and civilized visitor from another universe. In this case, it's the Librarian, who (ironically) had been pushed onto an evolutionary course away from humanity when he was turned into an orangutan.
• In Septimus Heap, the fifth book mentions that people in the past traveled to the Moon.
• Edgar Allan Poe's "Some Words with a Mummy" pokes fun at the then-common theory that Egyptians couldn't have built the pyramids without outside help: a revived mummy reveals to a group of scientists (all proponents of said theory) that his people not only built the pyramids on their own, but developed all kinds of crazy advanced technology which has since been lost — all without any interference at all, be it supernatural, alien, or European, plus having far longer lives than modern humans due to their superior medicine, showing up all the scientists. What an epic Take That!.
• In The Space Odyssey Series, the Precursors bring The Monolith to Earth to accelerate the evolution of primitive hominids.
• For the Star Wars Legends, Word of God says that ancient Coruscanti Humans who long predated the Republic were visited by a much more advanced alien race called the Columi, and were offended by their developing culture. Much material in this universe claims that the galaxy was once ruled by a very ancient civilization known as the Celestials, and were one of the galaxy's oldest civilizations. They were hinted to be responsible for the current alignment of the Corellian system, as well as making AWESOME floating space artifacts that put the technology in the original trilogy to shame. How they did this is still unknown to modern people, making them not unlike gods in their powers. Their fate is a mystery as well.
• The Takers, a modern Two Fisted Tale by Jerry Ahern. The log of a 19th century expedition seeking Atlantis mentions a horned 'demon skull', which sends the protagonists (and the villain) off on their quest. They discover an ancient yet fully-functional alien base under the ice of Antarctica, with a giant statue implying that the aliens passed on their genetic legacy to mankind.
• In the first The Thief of Baghdad novel, the protagonist is abducted by a UFO while stuck in "Arabian Nights" Days with Laser-Guided Amnesia. Due to his actions, however, the aliens get upset and leave Earth, never to return.
• Used, with time travelers rather than aliens, in Poul Anderson's Time Patrol story "The Sorrows of Odin the Goth". The time-traveling historian Carl knows that his travels among the Goths are liable to make the natives think he's a god, so he dresses in such a way that stories of his exploits would be folded into the preexisting mythology of Wodan (aka Odin). It doesn't work out quite how Carl intended it...
• "The Birthday of the World," a short story by Ursula K. Le Guin: its setting is not historical, but a fictional bronze-age civilization with Mayincatec similarities. The nation's God King is deposed after a shocking prophecy proclaims the arrival of a new God: it specifies that God has one eye, is white as snow, and that a great house will fall and burn. The narrator is a daughter of the royal family, and the ensuing chaos leads her to assume that the fallen house refers to her own. Pretenders try to claim the throne, including the narrator's warlord brother — he loses an eye in battle, covers his body in white greasepaint and claims A God Am I. In the midst of this civil war, the sky is lit by a bright streak like a falling star. The thing that burned and fell is a great house, and figures emerge from it. When she sees these "angels," the narrator knows the prophecy is fulfilled:
  "They were white all over, and hairless. Their heads had no mouth or nose and one huge single staring shining lidless eye. ... Around the eye was a ring of silver that flashed in the sun. I saw myself in one of those eyes, a pupil in the eye of God. Their snow-white skin was coarse and wrinkled, with bright tattoos on it. I was dismayed that God could be so ugly."
  • In this moment of Dramatic Irony the reader probably recognizes the astronauts before the awestruck protagonist does: they are not the Apollo astronauts but their reflective space-suits and visors are similar enough. This is also an Unexpected Genre Change as majority of the story has no science-fiction tropes.
  • An aversion of the way this trope usually goes, because these visitors from another world do not transform this one — to the contrary, the climate makes them sick and most do not survive more than a decade. At the end of so much tragedy, God Dies — but With Dignity.
• Possible but unconfirmed in David Brin's Uplift series. Every alien race after the Precursors was uplifted by another species and most refuse to believe that humanity evolved sapience naturally. Rather they claim that humans must have been abandoned by an irresponsible patron race before their uplifting was complete (this has apparently happened before in galactic history-such "wolfling" races tend to destroy themselves before reaching space). On Earth there's "Danikenites" and "Darwinists," the former wear togas to protests while the latter dress like cavemen.
• Fred Saberhagen's The White Bull invokes this trope to explain the minotaur legend. He's also used it with a not-so-ancient classic: in The Frankenstein Papers, the creature turns out to be an alien scholar who'd been snooping around the mad doctor's lab, curious about his electrical equipment, and been rendered unconscious and amnesiac by an accidental discharge.
• In The Wild Boy, it's indicated the Iani, the creatures who created the Lindauzi, also visited Earth and possibly spawned humanity-the two races are definitely related somehow.
• Area 51 reveals there is an alien species that has interfered with humanity throughout our history, and has maintained a presence into the modern day. They were the creators of most famous edifices (the Pyramids, the Great Wall of China, Stonehenge etc.). In fact two factions exist who have both battled each other for millennia, and their leaders took various guises (such as King Arthur) to win humans' support. Basically all myths of gods, ancient heroes and lost lands (like Atlantis) come from their past interference. This conflict boils over to the present in the novels. It's also revealed their species is combating another who's even worse. Humans, it turns out, were genetically engineered by them as soldiers to fight in this war. We're not even native to Earth.

Live-Action TV

• In Agents of S.H.I.E.L.D., as established in the rest of the MCU, Earth has been visited many times by aliens in ancient times, with two cases being relevant to the plot of the show:
  • The Asgardians, who were considered gods and left some of their technology lying around.
  • The Kree visited the planet and carried out experiments to genetically engineer humans into weapons for their war.
  • Enoch states that he's been observing humanity for 32,000 years.
• The History Channel has an entire series, Ancient Aliens, built around this trope. This◊ image macro sums it up. "I'm not saying it was aliens, but...IT WAS ALIENS."
• Babylon 5 examples:
  • The Vorlon appear to have inserted themselves into the mythologies of dozens, if not hundreds, of planets. When Kosh exits his encounter suit to save Capt. Sheridan's life in the season 2 finale, everyone watching sees him in the form of an angel as depicted in the respective religions of their people. The sole apparent exception is Londo, who says he sees nothing (given Centauri have telepaths and they're evidence of Vorlon meddling, he could have been lying. It could also be that Londo has been touched by the Shadows and that has blinded him to the angel projection of the Vorlons).
  • Sinclair is a human version of this to the Minbari. He is transformed to appear like a Minbari and pilots B4 back a thousand years to aid in the temporary defeat of the Shadows. He becomes their law giver with the name Valen.
  • Another one is the Great Maker. On most worlds (including Earth), he or something like him is the One God in monotheistic religions, but on Centauri Prime, he's worshipped as the head god and there is empirical evidence of him showing up to teach the Centauri the basics of civilization...and attack the Xon, the other sentient race of their homeworld, blasting them with "hands of wrath".
  • Also according to the Book of G'Quan, a sacred Narn text, the Shadows placed a military base on Planet Narn one thousand years before the series begin (thus in Narn's primitive times as the Narn are even younger than humans as space-faring races go) but were expelled thanks to the then existing Narn telepaths who were wiped out in the process.
• Battlestar Galactica (1978), having been produced at the height of the craze, strongly implied that this was the case in its universe, as the Galactica encounters sufficiently advanced aliens with more than a passing similarity to angels as perceived in the Mormon religion. The 2000s series goes a step further, explicitly identifying the "Lords of Kobol" with the Twelve Olympians of classical Greek mythology, though how the Colonial religion and Greek religion are linked has yet to be explained.
  • The Colonials themselves, if their costuming is any indication, are also meant to be these or some sort of Precursors. Their starfighter pilots wear "Pharaonic" helmets evidently meant to have inspired Tutankhamen's burial mask, and bridge officers wear a very distinctive octagonal cloak, like the classical Greek chalmys. The missing 13th colony, which they're looking for, is Earth. (In The Original Series they find it. They find it in the new one too, but because the new one is Darker and Edgier, it's been nuked to hell and gone).In the finale of the new series, it turns out that it wasn't our Earth that was nuked. It ends with the survivors settling on our planet, which they name Earth — about 150,000 years ago, meaning this trope applies to the entirety of the show.
• In the New Zealand series The Boy from Andromeda, the titular character is a blue-skinned Human Alien who crash-lands on Earth after his ship is shot down by the very weapon he came to disarm, an ancient cannon built into a volcano that erupts when it fires. The Andromedans are the ones who put the weapon there in the first place millennia ago, but now it threatens their refugee fleet on its way past the Solar System to their new home. Even worse, when charged to full power, the weapon will not only destroy the fleet but will also create a supervolcano-like eruption, effectively destroying human civilization. The weapon is protected by the Guardian. The alien boy attempts to defeat the Guardian but is shot instead. In the end, the main heroine realizes that humans are (at least, in part) descendants of the Andromedans to came to install the cannon. Thus, she is able to deactivate the Guardian and stop the weapon.
• Kolob in Children Of The Dog Star is one of three alien space probes from Sirius that imparted advanced knowledge to ancient people, including the Dogon.
• Doctor Who has featured this in several stories:
  • "The Dæmons" reveals the existence of a race of aliens that resemble demons from classical art, and suggests that they were objects of worship for ancient and medieval pagans.
  • "Death to the Daleks": The Doctor suggests the Exxilons might have traveled to Earth and taught the Peruvian Incas how to build their pyramids, as they were too "primitive" to do it themselves. That would be the primitives who developed everything from terraced farming to brain surgery.
  • "Pyramids of Mars" identifies the Egyptian gods Sutekh and Horus as alien warlords, the mythological account of the war between them being a recollection of their actual conflict.
  • "The Stones of Blood": Cessair was an alien who also took on the identity of Vivien Fay, Morgana Le Fay, The Goddess and The Cailleach. Also, her Ogri hid as some of the stones in Stonehenge and were possibly the inspiration for ogres, Gog and Magog.
  • "Battlefield" implies that a future regeneration of the Doctor was/will be Merlin of the Arthurian legend and thus influence the development of England in the deep past.
  • "The Satan Pit" hangs a lampshade; the Beast claims to be an Ancient Astronauts version of the Devil, but the Doctor is highly skeptical, pointing out all the various examples of the trope in different cultures on different planets. Russell T Davies describes this episode as a "sequel" to "The Dæmons". It's also left ambiguous as to whether the Beast actually is the Devil (as in, the real deal) or is a Sufficiently Advanced Alien who has just served as the inspiration for that mythological archetype throughout the ages and galaxies.
  • "The Pandorica Opens": Stonehenge is actually an alien communications array surrounding the Universe's strongest prison, the Pandorica. The Pandorica is presumed to hold Sealed Evil in a Can, but actually turns out to be a trap for the Doctor.
  • "The Lie of the Land" lampshades this trope as the Monks brainwash almost the whole of humanity and, in order to justify their new rule over Earth, pose as aliens who have arrived in primeval times and guided humanity's development ever since.
• Earth: Final Conflict:
  • Ma'el, a Taelon scientist, traveled to Earth thousands of years ago in order to determine if humans could be turned into soldiers to be used in the Taelon-Jaridian War. However, once here, Ma'el grew fond of humanity and changed his mind, sending a warning message to the other Taelons, telling them not to come. He also gave some humans Psychic Powers in order to foster better communication between the races. As revealed in the episode, where Liam and Augur end up in a parallel world, Ma'el also encouraged humans to urbanize, believing that it was the only way for humanity to develop the necessary industrial and scientific infrastructure necessary to resist his people, should they ignore his warning and come anyway. In a last-ditch effort, he befriended a Roman man and tasked him with acting as his scout through the ages, sleeping in the stasis pod aboard Ma'el's buried ship, periodically waking up in order to assess the state of humanity and look for any alien presence. Should the Taelons ever arrive and prove to be harmful to humanity, the Roman is to activate the ship's final protocol, causing it to lift off and accelerate on a collision course with the Taelon mothership. In the above-mentioned parallel world, Ma'el never comes to Earth, and his previously-militant attitude ends up influencing the modern-day Taelons to outright invade Earth instead of attempting to subvert humanity covertly. Meanwhile, that world's humanity never urbanized and lives in scattered hamlets, although they have somehow managed to develop advanced weaponry due to the constant fighting between the settlements.
  • Season 5 also reveals that prehistoric humanity used to be enslaved and kept as food by the Atavus, the common ancestors of the Taelons and the Jaridians. It's speculated that their leader Howlyn was so impressed with Renee (when she used a time-traveling ID portal to end up in the past) that he used the dead body of a Medieval monk to enhance the DNA of primitive cavemen to speed up their evolution into Homo sapiens sapiens (i.e. modern humans). Then a meteor storm forced the Atavus into slumber, allowing humanity to rise.
• The Outer Limits (1995):
  • In "Corner of the Eye", the aliens tell Father Anton Jonascu that their people visited Earth millennia ago and their teachings shaped the development of every human religion. However, like everything else they tell him, this turns out to be a lie.
  • In "Sarcophagus", while searching for evidence of an advanced Neolithic culture in the Wrangell Mountains in Alaska, a team of archaeologists discovers an amber-like cocoon in a burial chamber which has been undisturbed for 10,000 years. They initially believe that the skeleton in the cocoon belonged to someone with deformities, but they later come to the conclusion that he was an alien. After Curtis Grainger touches the amber, he begins to receive psychic images of the alien being attacked and killed by Neolithic tribesmen. From these images, he determines that the cocoon was placed in the burial chamber as the tribesmen thought that he was a god.
  • Discussed in "Joyride". Lil Vaughn refers to the theory that aliens seeded Earth with their DNA millions of years earlier and humanity evolved as a result. This is similar to the storyline of the earlier episodes "Double Helix" and "The Origin of Species", though those episodes involve Ultraterrestrials as opposed to true aliens.
• The Outpost: Season 4 reveals that the Prime Order and Blackblood religions were based on misremembrances of the Masters, a group of Physical Gods who travel between dimensions and feed on the life force of worlds in order to fuel their immortality, and who came to the series' world thousands of years ago. The seven kinjs that grant various characters across the series mystical powers originally belonged the Masters, and the Blackboods are descended from a hybrid child conceived when Aster, the Masters' Token Good Teammate, fell in love with a human woman.
• Quatermass:
  • The 1958 BBC TV serial Quatermass and the Pit (and the 1967 movie based on it) has the premise that beliefs in witchcraft and demons stemmed from the arrival of Martians early in Earth's history who attempted to engineer the hominids of Earth to become the successors of their own Dying Race.
  • The 1979 sequel serial simply titled Quatermass reveals another race of aliens is responsible for the existence of Stonhenge and other ancient stone rings. They were originally markers to warn of spots the aliens used to harvest humans.
• Mentioned in Red Dwarf, episode 4, where Arnold Rimmer explicitly points out the pyramids of Ancient Egypt as "proof" that there must be alien life in the universe. Lister retorts by replying that they moved such "massive blocks of stone" with the aid of "massive, massive whips".
• Resident Alien:
  • Harry mentions that his people helped the humans build Stonehenge.
    Harry: Bunch of idiots sitting around drinking mead, making us do all the work! Lazy Druids!
  • He later tells Max and Sarah that the Nazca Lines are in fact alien graffiti.
• Several episodes of SeaQuest DSV involve tall Grey-like aliens, capable of walking through walls (they're actually "silicon projections"). In one episode, they possess the bodies of several SeaQuest crewmembers and head to a Native American reservation, where it's revealed that the aliens have been to Earth before, long ago, and made contact with a Native American tribe. In their first appearance near the end of season 1 (one of the first episodes when the show really started to Jump The Shark courtesy of Executive Meddling), they're revealed to have been visiting Earth millions of years ago, long before early hominids evolved. At first, they don't even recognize humans as intelligent and don't want to communicate with them. They are interested only in the intelligent species that was around way back then and with which they had interaction: dolphins. So, in fact, they turn out to be Ancient Astronauts to the dolphins long before humans.
• In Smallville, tales of a Kryptonian visitor were the foundation of a Native American religion.
• The crew of Space Island One encounter a Babylonian space probe.
• Stargate SG-1 (and its sequel Stargate Atlantis) takes this to its logical extreme.
  • Virtually every culture's gods or mythic figures (right up to King Arthur) have, in the course of the show, been revealed to be inspired or co-opted by aliens of one form or another. Mostly, they were the Goa'uld, which began as the Egyptian gods and spread from there, though the benevolent Asgard were the Norse gods, and Merlin was a Sufficiently Advanced Alien. The Goa'uld were evicted from Earth several thousand years before the beginning of Christianity, although at least one group of early Christians were transplanted to another world by an unknown party, eventually evolving into a medieval society under the domain of Sokar, who co-opted the image of the Devil for his own purposes.
  • This was alluded to when Daniel explained how there is a point in human history where humans suddenly stopped worshiping fire (a representation of the Ori) and started worshiping pure white light (a representation of the Ancients, which are angelic)
  • SG-1 have also shown some Goa'uld posing as Greek Titans and Oriental gods, as well as Mayan crystal skulls as alien communication devices, and Aztec having their own alien descendants and ancestors. For example, the Mesoamerican deity Quetzalcoatl is an Omeyocan. However, Lord Zipacna posed as a Mayan deity of the same name, meaning not all Mesoamerican deities were Omeyocan.
  • One episode had the characters find themselves in what appeared to be a standard medieval Christian society, leading them to briefly discuss the possibility that a Goa'uld is posing as the Judeo-Christian God or even Christ. It's Teal'c who dismisses this idea first, having read the Bible and come to the conclusion that no Goa'uld would act as compassionate and benevolent as the one featured within, as they couldn't even comprehend such behavior. It turns out that the Goa'uld who rules the planet impersonates Satan instead.
  • The lost city of Atlantis wasn't sunk or lost: it launched into space and traveled to another Galaxy, eventually settling on a new planet. And then it was sunk, in order to hide it from the Wraith. The remaining Ancients traveled from Atlantis back to earth and presumably told the story of Atlantis to the ancient Greeks. Only leaving out that it was on another planet, in another galaxy.
• Star Trek: The Original Series has had a few of these, most notably Apollo (and by reference the other Olympians) and Kukulkan.
  • "Who Mourns for Adonais" is the episode featuring the alien claiming to be Apollo. "Plato's Stepchildren" is an episode featuring aliens who so admired classical Greek culture that they adopted it as their own. So the aliens from "Plato's Stepchildren" have only two degrees of separation from the aliens from "Who Mourns for Adonais"!
  • Kirk himself becomes a type of Ancient Astronaut in "The Paradise Syndrome", giving the transplanted Native American tribes knowledge of medicine, irrigation, and agriculture.
  • Humans also are Ancient Astronauts in the episode "A Piece of the Action": a text on Chicago gangs of the 1920s was accidentally left on Sigma Iotia II a century earlier. It subsequently became regarded as a holy book, and the inhabitants built their entire civilization around its depiction of gangland culture. At the end of the episode, they realize that one of their communicators got left behind, and Kirk suspects they'll be able to reverse engineer it...
• Star Trek: Voyager:
  • In the episode "Tattoo", Native Americans were barely intelligent cavemen until they were genetically uplifted by ancient aliens.
  • In the episode "Blink of an Eye", the crew of Voyager become Ancient Astronauts to a civilization on a planet that exists in enormously accelerated time; from the viewpoint of the planet, Voyager is in their sky for the sum total of civilization, and eventually they advance their technology to the point where they can go out into space to meet them. The aliens didn't know about the time dilation and by the time the explorers make contact it's more than a generation later on the planet and they start trying to shoot down the alien ship that so callously destroyed their peaceful explorers. A secondary motivation was that Voyager's presence was acting as a third pole for the planet, giving it frequent earthquakes. The ship is only saved when one of the explorers goes back to explain things, then returns to Voyager with ships specifically built to move Voyager out and break the time acceleration.
  • "Dragon's Teeth" involves a race of aliens who used a naturally occurring network of dimensional tunnels to carve out an empire. When their oppressed subjects eventually overthrew them, some retreated into cryostasis to wait for a more opportune time. By the time of the series, most cultures in the Delta Quadrant only remember them as cruel trickster demons in a few very old legends. For reference, in the time they ruled (about 900 years before the series timeline), they remember the Borg as being mostly harmless and confined to a few systems.
  • Then there are the Voth from "Distant Origin", who are descended from dinosaurs, having evolved on Earth millions of years ago and leaving during a cataclysm. After traveling for who knows how long, they settled in the Delta Quadrant and forgot their origins, with their official doctrine claiming that they are the first sentient beings to evolve in that part of space. To say otherwise is heresy. While they are undoubtedly more advanced than the Federation, they are not "millions of years" more advanced.
• Star Trek: The Next Generation:
  • The episode "The Chase" winds up establishing that aliens not only seeded primordial Earth with life, but also a vast collection of other planets, including Qo'noS, Vulcan, and Cardassia.
  • Subverted by the episode "Devils Due" where a con artist reads the myths of an alien world and realizes that modern technology is capable of providing all the signs and wonders she'd need to impersonate one of their deities.
  • Played with in regards to the Q Continum; Q, for instance, is every single trickster figure in every single mythology and religion on Earth (or so he says; Q lies so often that you can never be sure) but one would be hard pressed to argue that he's not also a god. Q also in one episode claimed to be the Judeo-Christian God, which Captain Picard finds laughable. Later in the same episode, Q claims that he merely knows God, and was there when He created humanity.
• Features rather prominently by the end of Tracker (2001). Cirronians visited Earth, hid the Vardian Doomsday Device to keep it safe, and interbred with humanity to create a guardian line. Cole also mentions things like Stonehenge and the Pyramids when he explains things to Mel. Most Migar folk belive it's a myth by the time of the series, but Mel and Cole find it's all true.
• The X-Files did this a fair bit in its Myth Arc episodes. In a bit of a twist, the ancient astronauts were the first intelligent creatures of Earth. They just left for some reason, and came back to find hairless monkeys had taken over their spot.

Music

• Paul St. John's Flying Saucers Have Landed is a musical tribute to this trope.
• The Jimi Hendrix song "Up From the Skies" from Axis: Bold As Love is from the point of view of an entity that has visited Earth once thousands of years ago during an ice age, and has come back to observe how things have changed:
  I have lived here before, in days of ice
  And of course this is why I'm so concerned
  And I come back to find the stars misplaced
  And the smell of a world that's burning
• The heavy-metal band Gwar have a great number of songs on this theme; it could, in fact, be said to be the central theme of their music (well, apart from violence). Almost all of their songs are written from the perspectives of a group of alien warriors (one played by each band member) who were banished to the Earth millions of years ago after becoming too violent and unpredictable even for their warlike Eldritch Abomination master to tolerate and now seek a way to leave the planet. The album "Lust In Space" focused particularly heavily on this theme.
• Doctor Steel was a firm believer in Zechariah Sitchin's theory that humanity was created by aliens that posed as gods to the ancient Sumerians, and also believed there was a secret alien illuminati still in control of world affairs. Several of his songs and videos reflect this belief.
• "Inca Roads" by Frank Zappa from his album One Size Fits All (1975) is a satirical deconstruction of this trope. In the first half of the song the protagonist wonders whether aliens made a vehicle fly to land in the Andes and "build a place to leave a space for such a thing to land." Eventually the song gets sillier as it is implied that the aliens only build them to have sex on them.
• Lemon Demon: "Ancient Aliens" is about a caveman struggling to bond with an extraterrestrial, implied to be the sole survivor of a spaceship crash.
  I'm not like you, you fly
  You burn my eyes, my eyes
  You speak in my mind
  Your kind all died when you arrived
  
  I saw you making fire
  Strange things happen for no reason at all
• Peter Schilling's "Error In The System" from the titular album seems to suggest that humanity as a whole has descended from them.
• Sun Ra built this trope into an entire concept. He claimed to have been born on Saturn and been abducted by aliens to come to Earth and spread a message of universal brotherhood so that mankind could be transported to another and better place in space. He mixed Ancient Egypt mythology and imagery with space concepts in his work and laid the foundations for the Afro-futurism movement in music.
• Chris de Burgh's "A Spaceman Came Travelling" is based around the idea of an ancient space traveller visiting Earth at the time of Christ's birth. His glowing spaceship stops above Bethlehem and resembles the Nativity Star — leading both him and the various visitors to the Virgin Mary and the infant Jesus to bring a message of peace and goodwill from the stars.
• Jorge Ben Jor's "Errare Humanum Est" questions if humanity's urge to explore the stars wasn't because "were the gods astronauts".
• Gamma Ray’s "Valley of the Kings" and its intro track "The Landing" on the album Somewhere out in Space are about aliens arriving on Earth in ancient times and being seen as gods by early humans.

Pinball

• In Mad Daedalus, a crashed spaceship provides the ancient Greeks with advanced feats such as genetic engineering and Time Travel.

Radio

• Journey into Space:
  • In Journey to the Moon / Operation Luna, the Time Travellers attempted to colonise Earth thousands of years ago.
  • In The Red Planet, the Martians were a race of giants and their visit to Earth gave rise to myths about giants, who were often believed to live in the sky.
• Directly parodied by The Burkiss Way, were a thinly disguised version of Erich von Däniken appears on a books programme to talk about the latest sequel to his Ancient Astronauts series of books, and is then abducted by the Ancient Astronauts themselves when they actually show up and demand a cut of his profits.

Tabletop Games

• Warhammer 40,000:
  • In a twist, the ancient astronauts in question are often the original human settlers of the various human planets, of whom knowledge was lost during any one of the several galactic dark ages, and most primitive humans thus regard the humans and technology of old as worthy of worship. The Imperium of Man and Adeptus Mechanicus think they have the right idea and enforce it galaxy-wide...
  • Another interesting twist from the setting are that humans are the Ancient Astronauts to other species. The Tau are one of the few species this happened to and who still exist; the ancient technology that the Tau found? A human ship that was supposed to wipe them out but was caught in a warpstorm. However, most other primitive species found by the Imperium tend to die via xenophobic planet cleansing.
  • Also applies to the Eldar and Orks, who were either manipulated or outright created by the Old Ones to help in their war against the Necrons. The Eldar in particular inherited much of the remains of the Old Ones' technology, particularly the Webway which allows them to travel through the setting's version of hyperspace safely (quite important when hyperspace is also Hell). It's also hinted that the same may be true for humanity, or alternatively that we may have been influenced by the C'tan — essentially the Necron's gods.
    • It's outright stated the Aza'gorod aka the Nightbringer inspired The Grim Reaper.
    • The Necrons and Old Ones were last in action 60 million years ago. The in-universe theory favored by Eldar is that humans evolved naturally from a line of mammals designed as little more than a link in the food chain.
• Warhammer Fantasy: Part of the Backstory. The "Old Ones" were a mysterious species that came from the cosmos in silver ships, they colonized the world and reshaped it into its current form. Knowing Chaos would one day appear in this reality and attempt to consume it, they started creating races with the objective of keeping Chaos at bay and even one day defeat them. They first created the Lizardmen as their servants, workers and soldiers, led by the powerful Slann, with their temple-cities built in a way to create a ‘geomantic web’, an interlinked matrix of natural earth-energy that encompassed the planet. The Old Ones would also create the other species from the setting: First, they created Elves, who were given mastery of magic, but they decided the Elves could not beat Chaos alone due to being frail and having a low birth rate. Then, they created the Dwarfs, who were higly resistant to magic and chaos corruption, but were too stubborn and would not adapt fast enough in the face of demon trickery. The next race created was Humanity, who had the magical aptitude of the Elves, the durability of the Dwarfs, and having a lot of adaptability of their own, however, they were extremly corruptible to the powers of Chaos due their short lifespan and ambition. Finally, their last were the Ogres, created by combining the best aspects of Men, Dwarfs and Elves, in addition to this, they are able to survive on just about any food, from meat to tree trunks to rocks. However, before their were properly instructed by the Old Ones, the forces of Chaos invaded the world and the Old Ones dissapeared mysteriously.
• The Ancients in Traveller abducted humans and dogs from Earth, spreading Humans around known space and modifying the dogs into the canine Vargr before disappearing in a war between their superintelligent leader Grandfather and his descendents leaving behind the psychic but less technologically advanced Droyne. They took the humans to be better subjects than their fellow Droyne were, and eventually fight for them in their wars, and the Vargr were created as an experiment in creating another servant race.
• Yu-Gi-Oh!:
  • Some writers have proposed that intelligent extraterrestrial beings have visited Earth in antiquity or prehistory and made contact with humans. Such visitors are called ancient astronauts or ancient aliens. Proponents suggest that this contact influenced the development of human cultures, technologies and religions. Chronomaly Crystal Chrononaut is based on this concept.
  • Chronomaly Mayan Machine is based on the "Maya Astronaut" of K'inich Janaab' Pakal, a ruler of the Mayan polity of Palenque. The Palenque Astronaut appears to depict a man controlling a spaceship. This ornately decorated five ton stone was discovered in 1952 in Chiapas, Mexico covering the Tomb of the Mayan King Pacal, at the Temple of Palenque ~ the only known Mayan Pyramid to contain a Tomb, as seems the case throughout Egypt
• Dragon Poker was brought to earth by demons around the fall of Pompeii, or so Hoyle's Rules of Dragon Poker would have us believe.
• In Rocket Age the Ahnenerbe invert this in their theories, stating that the Ancient Martians were actually Aryan Earthlings who invented space flight in the distant past and conquered Mars. Something or someone also left trilobites all over the solar system; it's theorised that they may be interstellar vermin. They can still be found on Venus and in the asteroid belt.
• In Pathfinder, ancient Osirion was influenced from behind the scenes by the Dominion of the Black, an alien cabal of various bioengineered species. The exact nature and purpose of this interference is not wholly known, but it's clear that it was only a small splinter faction doing it, as Golarion is too underdeveloped to interest the Dominion enough to sublimate.
• "Ankur Kingdom Of The Gods" has this as a major part of the setting. Taking place millennia in earth's past, aliens colonize earth to mine for gold and created humans as a workforce. While most humans in the city-states are not slaves, they are forced to live at a mostly bronze age level under a feudal system ruled by alien nobles.

Video Games

• Ar nosurge reveals that the Teru Tribe on Ar Ciel arrived a few thousand years ago as an advance party for the people escaping their dying home planet of Ra Ciela.
• In Fire Emblem: Three Houses trope is implied, with The Goddess Sothis, whose consciousness inhabits protagonist's body, being in legends said to have descended from the celestial body known as The Blue Sea Star. While Sothis herself does not talk much about her past, due to having a form of amnesia, and has immense powers bordering on divine, and is incredibly long lived, she is also a biological, physical entity capable of both dying and reproducing, who possessed knowledge of advanced technology, and was considered False God by some of her enemies, lending credibility to interpretation that she is a very powerful and ancient alien.
• The Masari from Universe at War: Earth Assault is a homage to this trope — an ancient alien species that inspired most of the ancient civilizations, and also the ancient Atlanteans. They went into stasis sleep eons ago before being awakened by the Earth being attacked by the Hierarchy.
• Mass Effect has a few variants. There is a sidequest planet that tells you that that the ancient Protheans studied early humans, though there is no evidence that humanity actually worshiped them, and the only advancements in tech that humanity got from them were the high-tech ruins found on Mars. However, the hanar, a different alien race, do worship the Protheans, due to the fact that, according to their mythology, the Protheans taught them speech, and possibly made them sentient.
  • Mass Effect 3 reveals that the Protheans took a very hands-on approach to the asari. Bring Javik to Thessia with you and he'll reveal that much of one of the older asari religions is based on their actions. They deflected meteor strikes, kept hostile races away, gave them gifts of technology, farming, basic math...Liara is staggered by the implications. It's not entirely clear how much of this is true; while a lot of it fits the evidence, Javik also has a habit of lying about his time for his own amusement. However, there is the obvious fact that the earliest depictions of asari gods look a lot more like Protheans than asari.
• In Halo, the Forerunners interfered with a number of other species, including humanity. However, that time came and went long before humanity kept records (about 100,000 years ago), and the Forerunners did not leave much on Earth to uncover (with the exception of the portal to the Ark), though it's strongly implied that our ancient flood myths (like Noah and his Ark) were directly based on the conclusion of the Forerunner-Flood War. However, the Forerunners left plenty of easily-found relics on other worlds, causing the Covenant to worship them as gods.
  • It was seemingly implied that Forerunners were actually humans, what with 343 Guilty Spark believing in the first game that he had somehow already talked to the Master Chief in the prehistoric past and the fact that much of Forerunner technology can only be activated by humans, among many other things, but Halo: Cryptum revealed that Forerunners were actually a separate species who were simply somewhat biologically related to humans. In fact, "prehistoric" humans had independently developed their own advanced interstellar empire, but ended up losing a war with the Forerunners. In the aftermath, humanity was stripped of its technology and forcibly devolved back to the Stone Age. Eventually though, some Forerunners decided that humanity might be worthy of inheriting their legacy after all (hence why humans can activate Forerunner tech more easily than other species). Guilty Spark's seemingly faulty memory might be due to the Forerunner geas (heritable genetic commands) placed on various human lineages, one of which apparently shares some relation with the Master Chief.
  • The San'Shyuum (AKA Prophets) had not only made contact with the Forerunners, but had actually fought against them alongside their own allied species... humans (how's that for irony?). After being defeated, the San'Shyuum at first got off somewhat easier than their human allies, as they were simply confined to just two planets from their former empire, but their advanced civilization was later wiped out when they tried to rebel against the Forerunners. Ironically, their descendants began worshiping the Forerunners, with one of their breakaway sects eventually founding the Covenant. Nonetheless, their near-extinction left a traumatic cultural memory, with Halo: Broken Circle implying that the reason why non-Covenant San'Shyuum are so technologically conservative (to the point where they refuse to study Forerunner ruins) is because they fear that their gods will punish them if they become too advanced.
• The Morrigi from the Sword of the Stars expansion A Murder of Crows apparently inspired the legends of dragons, feathered serpents and angels in humanity due to visiting our world thousands of years ago. When viewed from space, the lights of their cities form giant glyphs, resembling the Nazca Lines and Crop Circles, implying that these were inspired by the Morrigi as well.
• The Omega Stone lampshades its own premise (that Atlanteans built the world's great ancient monuments using sci-fi-grade technology) by including a cheesy "Aliens built Stonehenge!" paperback among the clues for the game's Glastonbury segment.
• Technically, the D'ni people from the Myst games ought to qualify, although they wrote their way to Earth instead of landing here. Subverted in that the D'ni stayed Beneath the Earth and strictly avoided contact with natives of this planet for millennia, and only heretical renegades like Gehn had the gall to claim they were "gods" to inhabitants of other Ages. However, there are signs in their history that a few of their number found their way to the surface long ago and commingled with humans. It's probable that descendants of the stone-loving D'ni had something to do with the building of the pyramids and other ancient constructions, and modern "explorers" who ventured into the D'ni cavern in Uru and found a home there are strong callbacks to this original lineage.
• In the Resistance series of PS3/PSP games, it is revealed that the Chimeran towers are millions of years old, and the Chimera were the result of experiments involving the DNA of an incredibly ancient and sentient, though not humanoid, species.
• The alien entity Lavos, in Chrono Trigger and Chrono Cross is revealed to had caused the final evolution step of neanderthal-ish hominids into humans and be the chief influence in the rise of the most magically and technologically advanced civilizations of the world.
• Although not set on Earth, the Might and Magic games are set on worlds and ships which are colonies of an ancient race.
  • Exactly how aware the inhabitants are of that varies from world to world. Enroth takes it to a point where it almost falls out of this trope (they actually maintain historical records dating back to the collapse of interworld travel).
• Star Wars: The Old Republic is filled with these. The most notable are the Gree and Rakata. The Gree were much older and advanced than the Rakata, though the Rakata were more widespread and influenced many galactic civilizations, despite their very cruel demeanor.
• Surviving Mars has multiple Mysteries which have to do with the PC making contact with, or finding the works of, alien life forms.
• Inverted in Super Robot Wars: Original Generation. Not only was all the super advanced Lost Technology on Earth created by Humans, but said Humans also spread to other planets in the distant past, handily explaining their liberal use of the Human Aliens trope.
• Star Control has the Arilou Lalee'lay. They've been visiting earth since the dawn of man and have inspired the myths of gods, fairies, and apparently had something to do with the pyramids. Their main goal was crafting humans to be invisible to the Eldritch Abomination that ate the Androsynth. They act more like proud parents than anything else.
• The Tales Series elves are aliens from a comet, of all things, called Derris-Kharlan, that is apparently a source of mana. And somehow these aliens are cross-fertile with humans.
• The Cuotl in Rise of Legends are a Mayincatec civilization which has been subjugated by aliens posing themselves as gods, who have given the humans impressive technology (that cannot be told apart from magic). However, game balance means that it's no more powerful than the Steampunk and Clock Punk technology of the Vinci and the "Arabian Nights" Days magic of the Alin.
• The bird-like Chozo in the Metroid series have been roaming our galaxy for millennia, leaving behind ancient ruins and bits of their highly advanced technology everywhere. It just so happens that these bits of technology are quite useful to a certain armored, cave-exploring bounty hunter.[It helps that the armor of said armored action girl is also of Chozo creation] The action girl herself is also arguably a Chozo creation, having been raised by them before they vanished and genetically modified to be part Chozo to ensure compatibility with her armor and other bits of Chozo technology.
• In Iji, both the Tasen and Komato are originally from Earth. They rediscover their home planet shortly before the game starts; unfortunately, they only realize this after Alpha Striking the surface.
• The Kushan themselves were examples in Homeworld, but they had forgotten their origins. They realize that they are not native to their planet when they rediscover the science of genetics and find that they are completely unrelated to any other form of life on the planet (except for a certain hardy rodent), while all other life is intimately related to each other.
• In Doom³, Earth has been colonized by ancient Martians — who seems to be humanoid creatures with the same size and width as humans — who teleported there to escape a demonic invasion. Some scientists ask themselves if the Martians are ancestors of Mankind.
• Inverted in Asura's Wrath. Despite looking like they would be an ancient civilization, the Shinkoku Trastrium Race the game centers on is actually a culture of Future made to look like Ancient Hindu Mythology and Buddhism.
  • The Stinger of the True Ending DLC shows that the game is actually playing this trope straight — revealing that the events of the game occurred 870 million years ago. The only noticeable difference is that the Statue of Liberty has been replaced with a statue of Asura, fist raised to the heavens. Although this difference raises another question — were the game's events 870 million years in our past or was the game in our future and The Stinger even further along and implying that even technological and social development is cyclical like reincarnation?
• Subverted in Persona 2: Innocent Sin . A conspiracy book known as the In Lak'ech suggested that civilization came from a group of now extinct Maian aliens called the Bolontiku (named after a group of nine Mayan underworld deities) and that their spaceship Xilbalba is under Sumaru City, which could lead the Humans into becoming Idealians, people who understand the meaning of life. Naturally, it's all fake. Then the book gets released publicly throughout Sumaru City. Due to qualifying as a rumor, it becomes true.
• In the backstory of Shin Super Robot Wars, a certain race fled their homeworld under the threat of Balmar. Split into different factions with different leaders, they attempted to flee. One group fell beneath Balmar's shadow, while another fled to the safety of the Dug. Finally, one staked their lives on traveling to an unknown, distant region of space. This faction formed the Mu culture.
• In Star Ocean: The Last Hope, it's revealed that Edge, Reimi and Crowe are result of genetic manipulation from splicing DNA with an ancient alien race named Muah. It's not stated how far they influenced Earth's old cultures though. However, in the ending, it's revealed that the Lemurisians are descendents of an Eldarian exploration mission. It's foreshadowed by the fact the symbols used by them are alike.
• In the X-Universe, the Ancients are this to the Borons, which explains the latter's wisdom. This is never stated in the games, but only in the Encyclopedia included in the Super-Box.
  • Completely averted with the Humans though; the Ancients never visited the Solar System.
• According to the backstory of Destroy All Humans!, the Furons visited Earth long ago and interbred with the locals, meaning that every human has trace Furon DNA, a necessity for a race that's now reliant on cloning to reproduce and thus your reason to wreak havok upon them. Destroy All Humans! 2 reveals the Furons weren't the only species who went to Earth for "shore leave".
• At the end of Star Crusader it turns out you are the ancient astronauts! Well, in one of two possible endings. After the war you have been fighting the entire game is won, the main character decides to retire on a primitive remote planet, where the locals give him the title "pharaoh"...
• Stellaris:
  • This is one of the many options you have should you come across a pre-spaceflight sentient alien species. If you have an observation post in orbit, a random event can end with a Great Pyramid constructed on the planet, built "to appease a deity descended from the sky."
  • The First Contact story pack focuses heavily on interactions with pre-spaceflight aliens, which can veer into this if the aliens are sufficiently primitive (i.e. the Iron Age or earlier).
  • The "On the Shoulders of Giants" origin opens with the civilization having already discovered traces of an ancient and long-gone civilization having intervened in their pre-history. Following the storyline reveals the species was involved in a genocidal war between two interstellar powers, but details vary. In some cases the species was a primitive protectorate of a more advanced race, while in others the species was one of the interstellar powers and was forcibly de-evolved by their enemy.
• Dragons in Final Fantasy XIV are revealed to have come from another star many eons ago and they have had some form of influence on man's history.
• In Endless Sky, the Saryds are implied to have visited Earth in the distant past, inspiring the myth of centaurs.
• They don't show up in Tropico 5, but if you build a tourist site on ancient ruins, you can pander to public enthusiasm about the idea by upgrading the site so that they display "alien" artifacts. This adds "Slob" tourists as an additional preferred tourist class for the site, indicating that it moved downmarket by pivoting to aliens.
• Sonic the Hedgehog
  • Shadow the Hedgehog: Black Doom planted a spare fleet of ships disguised as ruins in the Glyphic Canyon Zone 2000 years before the start of the game to gain a leg up for when he could finally invade Earth.
  • Sonic Riders: Zero Gravity: As hinted in the first game, the Babylonian civilization were actually aliens who crashed on Earth when their gravity-manipulation engine malfunctioned. Their advanced technology caused them to be mistaken for genies.
  • Sonic Frontiers: The oldest one of all so far, the Ancients were the ones who brought the Chaos Emeralds to Earth after they fled the distruction of their homeworld by The End. They ended up on Earth when the Chaos Emeralds were drawn to the Master Emerald. When the Ancients mutated into the Chao and their memories were left in the Koco, their ruins were used by the echidnas as a basis for the designs of their own civilization.

Webcomics

• Reversed in Earthsong, where it's the people who make up the myths that have been traveling elsewhere, but have only faint memories of their alien companions once they snap back to their own place and time.
• Inverted in The Inexplicable Adventures of Bob!, in that the dragons of legend started out as a pre-human civilization here on Earth, then left for another planet, effectively becoming an alien race. However, they got space travel technology from the Nemesites, an insectoid race from a nearby brown dwarf that has technically ruled our solar system for about 65 million years, ever since the dragons joined their empire in exchange for aid in rebuilding after their nuclear war (which was actually initiated by first contact).
• Played with in minus.. After reading about the theory, minus goes back in time to meet the aliens. She doesn't, but the effects of her visit leave a lot of seriously worried archaeologists.
• Amazing Super Powers: calls: reconcile your Hollywood Histories! Comes with a wink to Zechariah Sitchin (see below) teological... hmmm... exercises in Alt Text and a thematical hidden comic.
• Bug Martini translates the message of this trope as bluntly as they can.
• Wayward Sons: The protagonists are the astronauts, crashed on our planet and empowered with a Healing Factor and Personality Powers. They become the Greek gods, while the antagonists become the Egyptian gods.
• The seradin from Prophecy of the Circle are strongly hinted to be this, allegedly coming "from the stars" and leaving behind some high tech items, as well as a religion worshiping one of them.
• A variant in The Adventures of Dr. McNinja, where the Inoktek civilisation was founded by King Radical, who came from another dimension that was more advanced in a rather peculiar way. Way more radical at least.
• In Sarilho, an ancient satellite crashing down starts the story off. But the thing inside it could fit this trope.
• Parodied in the xkcd strip "Alien Visitors", which plays with the usual trope by having the aliens who would teach humanity to build stone monuments arrive thousands of years too late. "Alien Visitors 2" continues the story of the previous strip by having the aliens recommend technologies that humans have learned to be dangerous, such as a hydrogen blimp and lead gasoline, or inefficient, such as biplanes and Juicero.

Web Original

• In one of SF Debris' reviews of an episode of a Star Trek: Voyager wherein Ancient Aliens "uplift" Native Americans, he points out the unfortunate implications of this trope as being similar to the concept of White Man's Burden, except with (white) aliens.
• Void of the Stars has the Boskops and Ethra'Hirel, who were actually native to Earth, but were spacefaring and inspired multiple myths such as the myth of Prometheus.
• In Welcome to Night Vale, Erich von Däniken's theories are accepted knowledge by Night Vale's citizens, whereas the concept of evolution and the notion that the pyramids and other ancient structures were built by mere humans are considered fringe beliefs.
• Orion's Arm: The Muuh had supposedly come to out solar system a very long time ago, leaving artifacts on Titan. Given how unsuited Earth is for them, though (Muuh can only survive in ultra-cold temperatures like those on Titan), they probably didn't come down here.
• SCP Foundation: SCP-875 ("War Criminals"). The pictures inside the SCP-875 pyramid indicate that the SCP-875-3 Insectoid Aliens taught the ancient Egyptians how to build the Pyramids.

Western Animation

• Not always gods: In Transformers: Cybertron, the monsters of earth's myths were actually Decepticons who came to Earth long ago, and were since sealed away by Crosswise... until Starscream freed them again.
• This is also the Backstory of the Pretenders in Transformers: Super-God Masterforce. Things like the pyramids and Nazca lines were originally made to seal away the Decepticon Pretenders.
• The characters of Transformers: Beast Wars are accidental ancient astronauts when they discover they've landed on ancient Earth. They also discover the dormant original Transformers and primitive hominids, but leave before they can change anything too drastically.
  • Besides accidentally teaching the hominids how to use weapons.
  • Except for the Butt-Monkey Waspinator, who remains on Earth and is worshiped as a god by the hominids...'til they get tired of him eventually and send him flying back to Cybertron (literally).
• In the Gargoyles episode "The Sentinel", it was revealed that the heads on Easter Island were actually busts of an alien lifeform whose military post was located there where he served as a sentry during a long ago war. The other mythical gods and monsters were based on terrestrial Gargoyles or The Fair Folk, not aliens. Or on real monsters, apparently an offshoot of the Faerie now living in isolation.
• Jonny Quest: The Real Adventures also has this explanation for the Easter Island heads, although it was more of an accident: An alien researcher was trapped on the island after its volcano erupted and lava engulfed its ship. The heads were used as a protective forcefield.
• Futurama:
  • Inverted this in "A Pharaoh to Remember", which introduces a planet bearing a remarkable resemblance to pharaonic Egypt, then explains that they copied everything — including culture and space travel — from the Ancient Egyptians. As well as how to mummify their dead "so as to scare off Abbott and Costello."
    Fry: Yes! Insane theories: 1. Regular theories: a billion!^note This is before they explain that they copied the Egyptians.
  • In another episode they played this trope straight, with the pyramids being built by alien cats but they did so to rob Earth of its rotational energy, which seems to be a play on a Real Life theory that pyramids are giant hydrogen engines used to power a microwave power station, which in turn power starships in orbit.
• In Justice League Unlimited, two stranded Thanagarians become the architect for an ancient pre-Egyptian (per Word of God) culture. Which is ironic considering the Thanagarians themselves had this relationship with a monster who taught them how to be civilized in exchange for human (well, Human Alien) sacrifice. However, the episode also notes that the utopia the Thanagarians created fell apart a generation after they died, since the Egyptians never learned how to build the fabulous technology they were given or repair it.
• The cartoon Roswell Conspiracies: Aliens, Myths and Legends was all about how different kinds of alien had been living among humans from ancient times and were the origin of many of the human myths, folklore and legends (as the name implies...).
• In the short stop-motion animation Prometheus and Bob, part of Nickelodeon's KaBlam!, an alien called Prometheus descends to Earth in the early Earth pre-history and attempts to teach Bob, a Neanderthal-esque caveman, basic technologies and civilized behavior, but failing every time with painful and hilarious consequences, either due the meddling of a cunning monkey or Bob's own slow wit. In the first episode, he's revealed to be the cause of the first humans losing their full-bodied ape-ish fur coat after an accident with a laser.
• The Star Trek: The Animated Series episode "How Sharper Than a Serpent's Tooth" reveals that the alien being Kukulcan visited Earth in the distant past and was the basis for the Mayan god of the same name, the Toltec god Quetzalcoatl, and the Chinese dragons.
• According to Ben 10: Destroy All Aliens, the pyramids were made by Tetramands, and Stonehenge was a Galvan practical joke.
• Men in Black: The Series:
  • An episode has the characters deal with an awakened mummy, which turned out to be a Hyperian. Frank the Pug was brought in as their resident Egyptologist. Him and Jeebs end up opening a portal to Hyper. They see pyramids everywhere, and all the Hyperians dress in Ancient Egyptian fashions and worship dogs (specifically, pugs). Frank ends up temporarily being their god, until Jeebs takes off Frank's dogsuit.
  • Another episode mentions that once Earth belonged to the interstellar Arkanian Empire that built Atlantis thousands of years in the past, which motivates an Arkanian fanatic trying to rebuild the empire to take Atlantis out of the sea disregarding that it would cause a tsunami.
• In Scooby-Doo! Mystery Incorporated, these are revealed to be the primary forces at work in Crystal Cove in Season 2. Interdimensional beings known as the Annunaki utilize animals as vessels, causing them to talk and being responsible for a variety of mythological figures around the world from Egyptian and Sumerian gods to Sun Wukong and Quetzalcoatl, with talking animals such as Scooby-Doo being explained as descendants of these vessels.
• It is revealed in Steven Universe that the Gem Homeworld had plans to colonize the Earth (which would have entailed not only sucking out the planet's "life force" to make more Gems, but hollowing the planet out). Rose Quartz rebelled against these plans in the hopes of sparing Earth's developing intelligent life, which eventually led to a Great Off Screen War between Homeworld and Rose's rebel forces, who would eventually become the Crystal Gems. The Crystal Gems have even had an influence on Earth's history, though they try to minimize Gems' effect on the planet.
• In Rick and Morty, the battery of Rick's spaceship is powered by a miniature civilization that Rick in the guise of an alien has taught how to generate power through pedals, siphoning most of the energy for himself. The race itself is on the cusp of doing the same thing to another "teenyverse", who are also planning the same thing with their own mini-universe. When Zeep, the scientist heading the research in the first miniverse realizes this, he proceeds to see Rick as a cruel god.
• Probably the funniest and least serious example would be the Great Gazoo, a Little Green Man that befriends The Flintstones, although only Fred and Barney can see him.
• Another example is episode "The Secret of Easter Island" of the animated adaptation of Blake and Mortimer. Evil aliens from Markab visited Earth thousands of years in the past (specifically Easter Island) as part of their genocidal crusade against “inferior species”.
• In the Phineas and Ferb episode "The Lizard Whisperer", Doofenshmirtz discovers that the Ancient Egyptians used music to summon aliens in order to help them build the pyramids. He plans to use the exact same melody to summon his very own army of alien minions.
• In Dead End: Paranormal Park, one of the topics Norma plans to explore on her podcast is "Did aliens build the Pyramids, or are conspiracy theorists just racist?"
• Molly of Denali: In "Mystery in the Night Sky," there is an alien conspiracy theorist named Montey Cribbits who says that aliens built the Taj Mahal. Trini later finds out that this is false when she looks it up online.

Other

• The Wandjina deities of Western Australian Dreaming are often touted as evidence of ancient astronauts by all manner of western conspiracy kooks. This is due to the admitely peculiar nature of their depictions: circular objects surrounding their faces, which look like astronaut helmets, but are actually supposed to be haloes of feathers and lightning. Thankfully, Aboriginal activist groups have put the crazies in their place with legal copyright claims that have successfully eradicated most of this nonsense.
• Evoked hilariously in this clip of Conan O'Brien and Tom Hanks when presented with a birthday present.
• The idea was heavily popularized by Chariots of the Gods?, as mentioned above. The book was published in 1968 by Erich von Däniken, and quickly became a bestseller. It was copied lots of times, was made into at least two movies, and led to the Ancient Astronauts plot showing up in several of the examples here, such as Battlestar Galactica. He followed it with a long series of sequels, getting even more out there (in some cases also bizarrely racist, e.g. once "speculating" that races were genetically engineered by ancient aliens, Black people being a much inferior, abandoned variety in comparison with the Europeans). There's also the caveat he wrote the book that served as the Trope Codifier when imprisoned for tax fraud and needed money.
• Before Däniken there was Italian Peter Kolosimo (1922–1984), whose best-selling books such as Terra senza tempo ("Timeless Earth") were the first ones to present these kinds of ideas. In fact, Kolosimo was the major influencer of Däniken (read: Däniken ripped off Kolosimo). He was also a communist who quoted heavily from Soviet authorities — which plays into who heavily promoted this in the first place. After his death, he went into obscurity and his books are no longer published, but due to Däniken and later Tsoukalos, his ideas will be in pop culture and pseudoscience/conspiracy-circle currency for a long, long time. Besides Kolosimo, Däniken ripped off a lot of other people too. Robert Charroux, Louis Pauwels & Jacques Bergier, and Brinsley Le Poer Trench all wrote pre-Chariots of the Gods? books touting the theory that Däniken pretty clearly borrowed from as well. One supposes that's what you get when a convicted embezzler and fraudster (prior to writing this or later books, he served multiple terms in prison for different thefts) writes something.
• This trope parodied by this shirt from "Teach the Controversy".
• One extremely popular variant of this trope is the claim that the ancient civilization of Atlantis consisted of expatriate aliens. The absolute masterpiece of the early paranormal movement, the 1970s The Bermuda Triangle by Charles Berlitz, explores this angle. No sarcasm here: if you want to read about Alien Astronauts in the context of abandoned Atlantean technology causing planes to fall out of the sky, this is where you want to go.
• There is a book by a certain Wolfgang Volkrodt suggesting that von Däniken is wrong — gods of old weren't aliens, only a secretive elite of technology users awing the lesser people with "LOOK AT MY BALLOON, I'M A GOD." The guy, being an engineer, even provides plans for their steam engines. A similar theory states that the "highly technological ancient civilization" wasn't aliens, only Atlanteans and possibly Lemurians, who blew themselves to smithereens long ago.
• David Icke's book The Biggest Secret is a conspiracy theory claiming that not only did reptilian aliens found the great ancient civilizations of Earth, they also continue to rule the Earth from the shadows. Apparently they don't mind the masses knowing that they rule secretly, since they allowed the publication of that book. Either that or the reptilian data is misinformation fed to Icke, in order to discredit him as he got too close to the truth of The Illuminati (some conspiracy theorists who find his Reptilian Conspiracy theory too much for even them have claimed this).
• You can find a carving of an astronaut on the New Cathedral of Salamanca, built in the 16th century. Ancient astronauts? No. The engraving was created in 1992 by one of the artisans restoring the cathedral, continuing the tradition of church builders and restorers including a contemporary symbol as a "signature" of their work. The National Cathedral in Washington, D.C. also has a Darth Vader Grotesque. Stone By Day, Dark Lord of the Sith by Night...
• The theory of panspermia/exogenesis posits that Earth's life has an extraterrestrial origin, but a good portion of these theories are less "extraterrestrials intentionally planted the seeds for life on Earth" and more "meteorites with the chemicals needed to develop life happened to smash into Earth from somewhere else in the universe."
• Bible scholar Zechariah Sitchin firmly believed this was a fact. His supposed source? The Bible itself. His works, The Earth Chronicles series, detailed his studies and interpretations.
• Scientology, anyone?
• At least one guy believes that America invaded Iraq for Ancient Alien artifacts, namely a Stargate. No, really.
• The Tale of the Bamboo Cutter from Japanese folklore is considered by many literary scholars to be the original Science Fiction story, with Princess Kaguya (who came from the moon) being an Ancient Astronaut.
• The theory has been somewhat debunked regarding Stonehenge. A man working by himself is building a replica in his backyard using nothing but simple machines (mostly levers). He has proven that aliens didn't need to be involved. The other claims are similarly rejected by mainstream scientists.
• Visoki Decani, a 14th-century Serbian monastery, contains an icon of the Crucifixion with what looks like two UFOs.◊ Notable alien conspiracy theorists, like Erich von Däniken, have for decades considered this to be an evidence of UFO presence in medieval history. This "theory" was, of course, dismissed by the priests, who offered a more Biblical explanation of the painting.
• The Sirius Mystery by Robert Temple (1976) argued that the Dogon people of Mali knew that Sirius had a white dwarf companion star long before astronomers made that discovery, and that they could only have learned it from visitors from a planet that orbits Sirius. Experts dismiss this theory, but there's no consensus as to how the Dogon actually acquired their knowledge (either they could've learned it from 19th century contact with French astronomers, or the anthropological studies that Temple got his information from were flawed and garbled the actual Dogon mythology about Sirius).
• There are apparently some old archaeology that show some very weird things including: so-called Helicopter hieroglyphs at Abydos in Egypt, stone glyphs depicting a story about the Anunnaki (inhabitants of the planet Nibiru) mentioned in ancient Sumerian texts, a votive relief of the winged priest of Dudu at the Louvre, Hindu depictions of Vimanas, and the Dogu figurines in Japan. More on that here.
• A lot of these theories are based on older, explicitly racist ideas to explain why different ruins in the Americas or Africa "obviously" were not built by Native Americans and Africans, but lost white people. Naturally, as you'd expect the racist versions of these are still popular in certain circles, though even if not explicit they can be harmful, as they imply that non-European peoples wouldn't have had the technical know-how to create their own massive structures such as the Pyramids of Giza or the Great Wall of China.
• Some ancient Indian epics speak of the Hindu gods having flying palaces and various weapons with amazing effects that have been reinterpreted as being ancient aliens in aircraft who ruled over humanity. Other times, they are viewed as "only" advanced ancient humans. There's even a claim that nuclear warfare took place in ancient India. Partly it's based on an account in The Bhagavad Gita which sounds similar to its effects, and the supposed highed background radiation in the area.

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