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->''"The continental hinterland consists of deserts, jungles and rainforests. It also contains lost kingdoms of Amazonian princesses, volcanoes, elephants' graveyards, lost diamond mines, strange ruins covered in hieroglyphics and hidden plateaus where the reptilian monsters of a bygone era romp and play. On any reasonable map of the area there's barely room for the trees."''
-->-- '''''The Literature/{{Discworld}} Companion''''' on the dark continent of Klatch

Named after ''Literature/TheLostWorld'' by Sir Arthur Conan Doyle, this is, naturally, a geographic location off all maps.

They are usually found in remote locations, such as the center of large and barely explored continents (usually DarkestAfrica), the polar ice caps, or mysterious islands. They are often home to [[AdvancedAncientAcropolis lost civilizations]] with amazing LostTechnology, or to prehistoric animals that have managed to survive unchanged—aside from the fact that they [[KillAllHumans suddenly find humans delicious]]. Some Lost Worlds are [[EverythingTryingToKillYou almost ludicrously dangerous]] and populated by fearsome monsters, and still others are {{Magical Land}}s where AllMythsAreTrue. Prone to being destroyed by [[ApocalypseHow volcanic eruptions, floods, quakes, and/or bombs]] [[CataclysmClimax at the end of the book/film/series]], with the protagonists barely escaping.

[[TechnologyMarchesOn No longer popular (or even credible) with the arrival of satellite mapping and GPS]]. Most modern fictions that use this trope are set in the pre-satellite past. The Lost World has now been adapted to serve in even more mysterious places, such as outer space or deep underground. You are now much more likely to see a civilization thought long dead on an episode of Star Trek than on your modern action show.

AppliedPhlebotinum is sometimes used to explain why the area has stayed lost into the modern era; it's contained in a PocketDimension, or was created by aliens as a nature preserve, or some such HandWave. Occasionally treated more seriously, as a venue for playing with alternate evolutionary pathways.

It's worth knowing that some elements of this have happened in RealLife, even recently. However, they certainly don't match the scale of a true LostWorld. For example, you might have a tribe that has had no interaction with the outside world for hundreds of years, but not, say, an entire civilization. When it does happen, the LostWorld had been isolated for millennia due to some geological feature which made travel in and out too bothersome to try: the 3 miles wide crater of [[http://en.wikipedia.org/wiki/Mount_Bosavi Mount Bosavi]] is almost a textbook case, as it had been thoroughly explored just in 2009, [[TruthInTelevision which ended with discovery of at least 40 previously undescribed species]].

Two frequent lost worlds are the DesertedIsland and (in older works) MysteriousAntarctica.
Often a key element in a JungleOpera. May contain a CityOfGold.

----
!!Examples

[[foldercontrol]]

[[folder:Anime and Manga]]

* ''Manga/CageOfEden'' takes place on an island populated with anachronistic monsters. Birds from fifty million years ago, wolves from ten thousand years ago...and of course, they all want to kill the humans.
* In the ''SpiderRiders'' franchise, a place aptly named the "Inner World" exists deep beneath the earth in a gigantic cavern filled with plants, an ocean and giant humanoid insects.
[[/folder]]

[[folder:Comic Books]]
* The MarvelUniverse distills this trope into a place known as the "Savage Land." It is a tropical jungle ''in the middle of [[MysteriousAntarctica Antarctica]]'' filled with strange creatures, prehistoric beasts, warrior tribes, incredible civilizations and other great pulpy stuff.
** It was in fact created by aliens.
* TheDCU has "Gorilla City", with its own phlebotinum ("invisible force fields") used to hide it, and populated by ''[[EverythingsBetterWithMonkeys telepathic apes]]''. It's appeared on TV in both ''{{Superfriends}}'' and ''JusticeLeague''.
* ''{{Cavewoman}}'' is supposedly set in the late Cretaceous (with the [[JunglePrincess main character]] having arrived there by time travel) but everything can be found in the primal jungle from StockDinosaurs to giant snakes, [[FrazettaMan hominids]], [[BigfootSasquatchAndYeti yetis]] and... [[AllTrollsAreDifferent trolls]]. Plus, one of the issues is named "Pangaian Sea".
* Another LostWorld in TheDCU is "Skartaris" (a world located within the hollow Earth, accessible through a portal in the Arctic wilderness), which is the setting of Mike Grell's ''TheWarlord'' (though other DC Universe characters would visit there from time to time as well). An episode of ''[[JusticeLeague Justice League Unlimited]]'' is set there.
** Skartaris is named after the Volcano through which Creator/JulesVerne's adventurers made their ''Journey to the Center of the Earth''.
** Skartaris was {{retcon}}ned into being AnotherDimension. It cannot actually exist within the DCUniverse's Earth, which isn't hollow.
* A third [[TheDCU DCU]] example: Themyscira, also known as Paradise Island, home to Wonder Woman and the Amazons.
** Retconned into being able to travel around the world and through time itself.
*** Not much of a retcon- see Wonder Woman's SilverAge adventures.
* And a fourth: Dinosaur Island, the setting for ''The War That Time Forgot'' series. In ''[[ComicBook/DCTheNewFrontier New Frontier]]'', Dinosaur Island turns out to be [[spoiler:an ancient and malevolent organism called the Centre]].
* Marvel similarly had a dinosaur-inhabited island which Skull the Slayer tried to civilize while simultaneously fighting off an AlienInvasion.
** This was actually Earth's distant past, accessed by a time warp created by aliens.
* Likewise, Monster Island is the home of the Mole Man, a frequent foe of the ComicBook/FantasticFour. Its location seems to fluctuate between the Bermuda Triangle and just off the coast of Japan, depending on writers' whims.
** The Mole Man and his monsters have vast underground passageways all across the Earth. Quite possibly two Monster Islands?
* The ''ComicBook/{{Turok}}'' comic book series which had a pre-Columbian Native American and his younger brother Andar who enter a lost valley and get trapped in it. They call the dinosaurs which they encounter "Honkers".
** The later ValiantComics run and the [[VideoGame/{{Turok}} video games]] {{retcon}}ned it into being AnotherDimension called the Lost Lands, and promptly threw a ton of other things into said lands such as robots, aliens, and demons.
* {{Tintin}} discovered a lost pocket of the Inca civilization in ''Prisoners of the Sun''.
* Creator/AlanMoore had, as part of his ''ComicBook/TomStrong'' series, a WildWest town set atop a large mesa. It was ripped out of time and as an intended side effect, the people could not live without some alien fruit. Tom leaves them up there on the mountain, to use them as {{Redshirt}}s later on. The existence of sat-imagery is not commented upon.
* ''DonaldDuck'' has used this trope ''so'' many times. Usually when Scrooge dragged Donald and his nephews along to search for treasures.
* ''Franka'' finds one in a crater on a Phillipine island.
[[/folder]]

[[folder:Films -- Animated]]
* Paradise Falls from ''WesternAnimation/{{Up}}'' is a partial invocation of this trope. It's not particularly hidden, as Carl and Russell are able to find it with little more than a lot of balloons and a pocket GPS navigator. On the other hand, the film implies that it has remained unsettled because [[spoiler:AxCrazy Charles Muntz has been killing off any other explorers who've visited the area.]]
* ''WesternAnimation/IceAge3DawnOfTheDinosaurs'' used one to fit dinosaurs into the post-extinction ice age: the dinosaurs survived in an underground lost world.
* The Disney film ''Disney/AtlantisTheLostEmpire'' has the titular Atlantis.
[[/folder]]

[[folder:Films -- Live-Action]]
* Film/KingKong's home, which is generally referred to as Skull Island. In the original film, the island was never named, although its most recognizable feature, Skull Mountain, was named; likewise in the 70s remake, the only reference is to "the beach of the skull".
* Doyle's ''Literature/TheLostWorld'' was adapted as [[Film/TheLostWorld a silent film in 1925]], with effects by Willis O'Brien, who also worked on ''Film/KingKong''. The film was also adapted in 1960 (with [[SpecialEffectsFailure Giant Lizards in Makeup]] playing Dinosaurs), 1992 (with its own sequel--with Handpuppet Dinosaurs) and 1998 (pilot for the above mentioned TV series).
* '50s BMovie and ''Series/MysteryScienceTheater3000'' feature ''Film/LostContinent'', starring [[Series/{{Batman}} Cesar Romero]]. [[LeaveTheCameraRunning And it sure took some finding.]]
* The ''Franchise/JurassicPark'' films (a man-made example). The first sequel is actually titled ''Film/TheLostWorldJurassicPark'' and its plot borrows a lot from Conan Doyle's novel.
** Also subverted by this series. Both islands can be found on maps, and Isla Sorna is accessible by boat.
* Creator/AmicusProductions adapted Creator/EdgarRiceBurroughs' novel ''Literature/TheLandThatTimeForgot'' into a movie in the 1970s.
* Creator/TheAsylum also adapted ''The Land That Time Forgot''; in their version, made as a {{mockbuster}} version of ''Film/LandOfTheLost'', the Land that Time Forgot is a sort of cosmic eddy.
* ''The Land Unknown'' (1957) has a US Navy helicopter in MysteriousAntarctica crashing into a misty crater populated by [[SpecialEffectsFailure highly unconvincing dinosaurs]].
* The lost cave complex in the 1956 film ''The Mole People,'' in which the titular creatures live. They are enslaved by EvilAlbino Sumerians who arrived in the caves when escaping a flood thousands of years ago.
* It is implied in the ''Film/SuperMarioBros.'' movie that dinosaurs have escaped from the parallel dimension into our world and humans into theirs throughout history, which would make the parallel world a sort of "Lost World".
* The island in ''Film/SannikovLand'', which in legends is warmed by a volcano and therefore can be inhabited by a tribe called the Onkilon despite being in the far north.
* ''Film/UnknownIsland'' from 1948.
* Lagos Island is a fictional island off the coast of Japan. It's subverted in that it can be accessed via plane or boat, but people generally don't live there due to the population of large carnivorous dinosaurs. [[FromBadToWorse Oh, and the island was hit by nuclear radiation]] [[Franchise/{{Godzilla}} mutating said dinosaurs into city-destroying monstrosities.]]
* The LostWorld of Aphrodisia (home to the [[LadyLand all-female Lubby-Dubby Tribe]]) in ''CarryOn Up the Jungle''.
[[/folder]]

[[folder:Literature]]
* Neverland, from J.M. Barrie's ''PeterPan''.
* Creator/EdgarRiceBurroughs created a number of Lost Worlds.
** ''Literature/{{Pellucidar}}'', the hollow-earth dinosaur habitat, had its own series, and included a crossover with ''Literature/{{Tarzan}}''.
** ''Literature/{{Tarzan}}'' also stumbles across a number of Lost Worlds in Africa. These include:
*** Opar, first introduced in ''The Return of Tarzan'' (1913). This lost city is the last remnant of the world-spanning empire of {{Atlantis}}. It's especially notable because it's one of the only recurring lost cities in the series.
*** The Valley of the Holy Sepulcher, in ''Tarzan, Lord of the Jungle'' (1928). This valley was settled by two quarreling groups of Crusaders in the twelfth century, one of which claimed to have achieved the Holy Grail and thus the Crusade, while the other denied it. The latter group founded the city of Nimmr at one end of the valley, blocking the path of retreat to England, while the former group founded the City of the Sepulcher at the other end, blocking the route to the Middle East. The two groups have long since ceased any serious efforts to leave the valley, and have come to various accommodations with one another for their own survival.
** Caspak (aka Caprona), a LostWorld within MysteriousAntarctica, the setting for the novel ''Literature/TheLandThatTimeForgot'' and its sequels.
** ''The Lost Continent'' (originally known as ''Beyond Thirty'') - the titular continent is Europe, in an AlternateHistory in which WorldWarI never ended because eventually no organized government was left to make peace. The United States never entered the war, and in fact made laws forbidding any ship to cross certain lines of longitude (hence the original title).
* ''Literature/TheLostWorld'' by Sir Arthur Conan Doyle is the TropeNamer.
* Creator/RobertEHoward's SolomonKane encountered some of these in DarkestAfrica. In particular, "The Moon of Skulls" featured a lost city that is all that remains of a once-vast empire which began as an outpost of {{Atlantis}}.
* In ''Literature/AtlasShrugged'', Galt's Gulch is hidden within the mountains of Colorado with AppliedPhlebotinum. Its use as a sanctuary for embattled egoistic industrialists has a sort of DeusExMachina quality about it.
* As mentioned in the quote above, ''Literature/{{Discworld}}'' is full of lost lands, mostly on the vaguely African continent of Klatch. Some of them are especially lost because they move about; these are called "brigadoons". It also had two mysterious and near-mythical continents, the Counterweight Continent and Ecksecksecksecks, both of which are now thoroughly (re)discovered (although the inhabitants might insist that they've (re)discovered the main setting of the books).
* Creator/JulesVerne's ''Literature/JourneyToTheCenterOfTheEarth''
** Several recent authors such as James Rollins or Jeff Long have followed Verne's example, placing their modern LostWorld tales underground, to justify such places having gone undiscovered.
* ''{{Dinotopia}}'' plays this trope about as straight as possible.
* DocSavage encountered several {{Lost World}}s, the most significant being the lost Mayan kingdom that provided him with the gold necessary to carry on his crusade. Several of these {{Lost World}}s are also [[CityOfGold Cities Of Gold]].
* ''The Diamond as Big as the Ritz'' by F. Scott Fitzgerald is all about an isolated pocket of fantastic wealth hidden in Montana. It's been successfully hidden by its wealthy, urbane, and autocratic owners for generations - but by the time of the story airplane overflight becomes a problem ...
* [[DeathWorld Henders Island]] from ''Literature/{{Fragment}}'' plays this so literally it hurts.
* The Hy-yi-yi islands, home of the [[http://en.wikipedia.org/wiki/Snouters Snouters,]] are a LostWorld without the ruins. Lots of goofy-looking critters, but for once they're not trying to kill you.
* In the Chinese fable ''The Peach Blossom Spring'' under the pen of [[http://en.wikipedia.org/wiki/Tao_Qian Tao Qian]] (Tao Yuanmíng, c365-427 AD), a fisherman stumbles upon a secluded Utopian village. The friendly villagers explain that their ancestors were driven to seclusion by political strife centuries ago, and have since lost contact with the outside world. The fisherman leaves a few days later, having been requested to keep his adventure a secret. Despite having marked his way out, he never finds the place again.
* ''A Strange Manuscript Found in a Copper Cylinder'' by James De Mille is another early example.
* Jane Gaskell's ''Literature/{{Atlan}}'' series centers on the adventures of a displaced princess exploring a civilized prehistoric world "before the continents had changed." The first novel, ''The Serpent'', is primarily a JungleOpera; its immediate sequel, ''The Dragon'', ends with the heroine entering Atlantis (or Atlan, as the saga calls it); the third, ''Atlan'', picks up when she becomes empress of the continent. The fourth book, ''The City'', is another JungleOpera, and the final book, ''Some Summer Lands'', explores the last days of the dying continent of Atlan. The first two novels even include a bibliography of (in some cases, discredited) research materials, primarily focusing on prehistoric life.
* In the original book ''TheWonderfulWizardOfOz'' by Creator/LFrankBaum, the Literature/LandOfOz is a remote country that's surrounded by a vast, unpassable desert, keeping it isolated from the rest of the world. Sequel novels would establish that there were several other "fairy countries" bordering Oz's desert, all located on an unnamed continent somewhere in "the Nonestic Ocean". Baum was never clear about what region of the world this was supposed to be in, though a popular [[{{Fanon}} fan theory]] places it somewhere near Australia. Anyway, one of the sequels had a magic spell make Oz and its neighbors invisible to the outside world and reachable only through magic, so this became something of a moot point.
* The AlcatrazSeries of books takes this trope UpToEleven: something like half the Earth's surface is made up of {{Lost World}}s called the Free Kingdoms where all sorts of magical and nonsensical things exist. They only go unnoticed because almost all the world's books, maps, and other sources of information are controlled by [[MilkmanConspiracy an ancient conspiracy of Evil Librarians]] who [[TheMasquerade don't want you to learn the truth]].
* There are two such places in Steve Alten's {{Meg}} series. The first one is the Marianas Trench, which is where the titular Megalodons are found. Its [[DownplayedTrope downplayed]], as people already knew of its existence, it just contained a prehistoric creature or two. Playing it much more straight is the Panthalassa sea in the sequal, Hell's Aquarium. Its a primordial sea contained under a rock ceiling at the bottom of the pacific ocean, and is home to an abundance of ancient sea creatures which have formed a comfortable food chain.
* The underground empire of K'n-yan in Hazel Heald's short story "The Mound" (revised, if not entirely ghost-written, by Creator/HPLovecraft).
* The ''{{Tunnels}}'' series has the Garden of the Second Sun, where it is theorized that many stages of evolution missing from the fossil record took place. It's also based heavily off of [[ThoseWackyNazis Nazi theories about a hollow earth;]] see the entry in Mythology below.

* DimeNovel hero Literature/NickCarter runs into a lost civilization of Old Norse speaking Amazons in Bolivia.
[[/folder]]

[[folder:Live Action TV]]
* ''GilligansIsland''
* The ''Series/LandOfTheLost''
* The various places encountered in the Bermuda Triangle by the characters of 1977's ''TheFantasticJourney''.
* A 1999-2002 series based on the titular story was called ''Series/SirArthurConanDoylesTheLostWorld''.
* ''Literature/TheLostWorld'' was also adapted as an A&E miniseries, in association with the ''WalkingWithDinosaurs'' guys, starring Bob Hoskins, James Fox, and Peter Falk. It was a bit more faithful to the source, but - more importantly - the deviations they made were [[AdaptationDistillation actually effective]].
* As stated above, ''Series/{{Lost}}'''s Island would certainly fit this trope.
** For those curious, it can't be found by normal means because it's constantly moving, possibly invisible and has a barrier around it so that if you don't go in at exactly the right bearing you'll become unstuck in time and likely die.
*** Most of the above conditions (the time warping and constantly moving parts in particular) were inadvertently caused by Ben [[spoiler: when he jammed the donkey wheel to move the island]]. Before and after that event, there are other ways to get into the island, like through a submarine or helicopter. Still, regardless of the method, they all share the same problem with being impossible to enter or escape without a very specific coordinates to squeeze through the barrier.
* ''Journey to the Beginning of Time'', a Czech film that was syndicated to American TV, most notably on ''GarfieldGooseAndFriends''.
* The ''Danger Island'' segment from ''TheBananaSplits''.
* ''{{Sanctuary}}'' has Hollow Earth, a subterranean city with incredible technology.
** The city of Praxis was built deep underground nearly 8000 years ago by humans and [[DifferentlyPoweredIndividual abnormals]] fleeing from a [[OurVampiresAreDifferent vampire]]-occupied Earth. Since then they have been steadily progressing their technology without any major wars or religious strife.
** Unfortunately, [[spoiler:Adam destroys Praxis by using a TimeDilation device]].
* Wherever the hell ''TowerPrep'' is. It gets sent into this territory because it is full of flora and fauna that shouldn't coexist near each other, and the constellations don't match up with anywhere in North America.
* Kinkao in ''PairOfKings''.
* The ''Series/{{Danger 5}}'' episode "Lizard Soldiers of the Third Reich" has [[MadDoctor Joseph Mengele]] performing sinister experiments in a LostWorld tropical plateau [[MysteriousAntarctica in Antarctica]] where dinosaurs, dinosaur-men, jazz-loving ape-men, and NubileSavage women coexist. After Danger 5 arrives there, we receive a [[{{Technobabble}} ludicrously nonsensical explanation]] for how the plateau has been isolated for 65 million years.
[[/folder]]

[[folder:Mythology]]
* {{Atlantis}}, the mythology of which at least predates Plato. A small continent made of seven concentric rings that allegedly sunk beneath the ocean. The Ur-example of literally countless lost, missing, or floating continents in Western culture.
* The continent of Mu.
* Shambala (sometimes Anglicized as Shangri-la,) a retreat somewhere in the Himalayas that's home to advanced technology and many demi-gods and saints.
** Although it is widely considered to be more like a metaphoral "state" and not a physical place.
* Lemuria, which was believed to be somewhere in the Pacific.
* The {{Ghostapo}} (Nazi occultists) believed, among other things, that the Earth was a hollow sphere with a second sun in the center. Another civilization thrived in the inner Earth which could be accessed through a giant hole in the polar cap. Predates the [[ThoseWackyNazis Nazis]] though; an old alchemical aphorism states: ''Visita interiora terrae rectificando invenies occultem lapidem''. (Visit the interior of the Earth to find the PhilosophersStone.) This goes back at least to the period of TheChymicalWeddingOfChristianRosenkreuz.
** Actually, the Hollow Earth theory wasn't just held as true by the Ghostapo, it was a ''very'' popular theory when it was introduced. It explained the subtle magnetic changes that the Earth experienced, and why Magnetic North sometimes changes. Combined with the fact that few people had ever been to either of the poles...
* The lost oasis of Zerzura, supposedly a lush, verdant valley hidden somewhere in the Sahara.
[[/folder]]

[[folder:Pinball]]
* {{Atari}}'s ''Pinball/MiddleEarth'' pinball takes place in one of these, complete with [[PantheraAwesome feral cats,]] [[StockDinosaurs bloodthirsty dinosaurs,]] [[KillerGorilla giant apes,]] and [[{{Kaiju}} even bigger monsters.]]
[[/folder]]

[[folder:Tabletop Games]]
* ''Lands of Mystery'', a supplement for the 1980's pulp game ''JusticeInc.'', was all about gaming in a Lost World setting. About half the book was taken up with Zorandar, a setting/campaign that had everything from dinosaurs to a lost Roman colony.
* The ''DungeonsAndDragons'' game-setting of ''{{Mystara}}'' has a long history with this trope, featured in such classic adventures as "Isle of Dread" or "Night's Dark Terror". The Hollow World boxed set converted the interior of the planet into a massive LostWorld a la Pellucidar, chock full of prehistoric creatures and lost civilizations.
* The ''[[DeathWorld Zendikar]]'' setting in ''TabletopGame/MagicTheGathering'' is an entire ''plane'' of this, complete with mystical artifacts and [[DoomyDoomsOfDoom horrible death at every turn]] for everyone from [[{{Mooks}} Goblins]] to ''[[PhysicalGod planeswalkers]]''. [[spoiler: [[JustifiedTrope Justified]] in that it doubles as the [[EldritchAbomination Eldrazi's]] [[SealedEvilInACan can]].]]
* ''TabletopGame/SpiritOfTheCentury'' readily embraces this possibility due to its strong 1920s era pulp foundation. While no such places are directly described in too much detail, it's suggested that several exist in DarkestAfrica (most notably, the kinds of places where Gorilla Khan's will is law) and there's a small hint of a lead for a GameMaster to potentially follow about a journey to the Earth's core being planned in the sample adventure provided in the book.
* The titular Hollow Earth of ''HollowEarthExpedition'' is all about this trope, featuring never ending jungle, lost civilizations, dinosaurs, and increased healing rates.
** ''Secrets of the Surface World'' supplement. One of these exists on a plateau in the Amazon rain forest. A British expedition reached it and returned, without any proof of their findings but with a fortune in uncut diamonds (a ShoutOut to Sir Arthur Conan Doyle's novel ''Literature/TheLostWorld''). There's a hint that the plateau connects to the Hollow Earth mentioned above.
* ''TabletopGame/{{Pathfinder}}'' has the Vaults of Orv deep below the surface of Golarion. One illustration has a giant Tyrannosaurus fighting an eldritch abomination in a jungle.
* ''TabletopGame/{{Exalted}}'': The world is full of unexplored or once-civilized places, but the Exalts can take it to the extreme: when [[EldritchAbomination She Who Lives in Her Name]] [[EarthShatteringKaboom destroyed ~90% of the world]], bits and pieces of it were thrown back into The Wyld; theoretically an Exalt with strong Wyld resistance can journey in it find things that were lost, up to and including ''worlds''.
[[/folder]]

[[folder:Theatre]]
* The musical ''Theatre/{{Brigadoon}}'' has its eponymous town surrounded by a mysterious fog in the Scottish highlands. The two American hunters who stumble upon it ask why there is no Brigadoon on the map, and eventually get a good answer: the town and its inhabitants vanished in an 18th century miracle, and only reappear for one day every hundred years.
[[/folder]]

[[folder:Video Games]]
* ''VideoGame/EarthBound'' has the aptly named Lost Underworld, an enormous underground cave. Unlike other areas of the game, the camera is zoomed out and your party is dwarfed by the jungle and [[EverythingsBetterWithDinosaurs gigantic carnivorous dinosaurs]].
* ''Franchise/{{Ultima}}'' loves this trope almost as much as DCComics:
** In ''VideoGame/UltimaIII'' and ''[[VideoGame/UltimaVII VII]]'', the legendary island of Ambrosia. Particularly odd because in the latter case it would seem to be in the way of shipping.
** In ''VideoGame/UltimaV'', a cavernous Underworld complete with shipwrecked sailor and lost expedition. In ''[[VideoGame/UltimaVI VI]]'' we learn that there's an entire civilization even ''deeper'' underground. [[spoiler:Well, "underground" from OUR perspective. They live on the opposite side of a flat Earth.]]
** ''Worlds of Franchise/{{Ultima}}: Savage Empire'' is set in Eoden, a copy of Doyle's Lost World complete with lost tribes, dinosaurs, and a "Dr. Livingstone, I presume" moment.
** In ''VideoGame/UltimaVIIPartII: Serpent Isle'', Serpent Isle has been missing from the maps since the end of the first game.
* Gaia's Navel in ''VideoGame/ChronoCross'' is at the center of an inaccessable island (you have to be flown there). It's basically 65,000,000 B.C. from ''VideoGame/ChronoTrigger'' in the modern day - it even has a younger {{Expy}} of Ayla, Leah, who joins your party [[spoiler: and is implied to be her mother]].
* ''VideoGame/PokemonMysteryDungeon 2: Explorers of Time/Darkness'' features one of these in the penultimate level, the aptly-named Hidden Land. The Hidden Land is so-called because it is ''only exists within a split second of time,'' meaning that [[TimeStandsStill time must be stopped]] before it can be visited.
* Although dinosaurs are not exactly unknown in the rest of the world, Un'Goro Crater of ''VideoGame/WorldOfWarcraft'' has a distinct LostWorld design.
** The Sholazar Basin in Northrend also qualifies.
*** And as of ''Mists of Pandaria,'' the Isle of Giants.
* The ''VideoGame/{{Turok}}'' {{FPS}} videogame series, which were loosely based on the comic book, although the player character is a modern day Native American who gains access to modern weapons during the course of the game.
** See above, the player character rampages through the 'Lost World' valley (among other settings) that the original comics were set in.
* The DS port of ''VideoGame/ChronoTrigger'' adds the [[ThatOneSidequest Lost Sanctum]], which allows a village of reptites to survive at least until the middle ages. Inside of a mountain, so it's somewhat understandable that no one can find it.
* The "Lost World" level in ''SonicAdventure'', located in the middle of the Mystic Jungle.
* The Lost Hex, from the appropriately named ''VideoGame/SonicLostWorld'', is a PatchworkMap FloatingContinent made of hexagonal pieces.
* [=LaGias=] from the ''Elemental Lords'' portion of the ''VideoGame/SuperRobotWars'' mythos. Like Skartaris it's a bit inconsistent whether it's a true hollow earth or just a parallel universe that's accessible through portals hidden underground.
* ''EVEOnline'' recently jumped on this trope with wormholes that open up into "Sleeper" space. Along with several other races they were thought to be extinct. WildMassGuessing ranges from time loops to returns to Earth's galaxy though they are much more advanced now. WordOfGod has been very silent on the matter. Also Earth itself qualifies due to the collapse of the Eve Gate.
* ''VideoGame/SkiesOfArcadia'' has Ixa'taka, a lost continent beyond the supposedly impassable South Ocean.
* In ''VideoGame/{{Xenogears}}'', many islands and whole continents of the world are missing from maps and unknown by most of the world's inhabitants, who have actually [[LaserGuidedAmnesia been programmed not to notice them]] through an [[AppliedPhlebotinum infection]] called -the Limiter-. After the Limiter is lifted between disc one and disc two, disc two conveniently has a much more featured world map with lands the TrueCompanions have not yet explored. It turns out that the missing lands were places that [[TheEmpire Solaris]] decreed that the planet's inhabitants should forget.
** Halfway correct. Those continents/islands aren't visible because until the middle of the game, they weren't even on the same physical plane as the landmasses that the player is exploring. After the destruction of a certain dimensional generator, the space time barrier separating those landmasses that were 'on the other side' are now accessible. Note that an individual/ships can still pass from one 'plane' to the other with the proper technology; this is offhand referenced a few times throughout the game.
* Each of the ''VideoGame/Uncharted'' games has one of these. The first game has a lost spanish colony on a small pacific island, the second has Shambala in the Himalayas and the third has the "Atlantis of the Sands" in the middle of a vast, barren part of the Arabian desert. Considering the game takes place in the modern day and all are open to the sky, it's never explained why none of them have been discovered accidentally before now.
* ''VideoGame/DragonQuestVIII'' has one where you go to the dark world.
** In fact, every ''VideoGame/DragonQuest'' game from ''VideoGame/DragonQuestIII'' onward has one.
** Technically, in ''VideoGame/DragonQuestIII'', you ''start'' in the lost world.
** ''VideoGame/DragonQuestVII'' has all but one island of the world be lost.
* The ''LostPlanet'' series takes place on a literal LostWorld, populated by giant creatures and hidden treasures.
* ''Return to Mysterious Island'' and its sequal play this fairly straight, the second game moreso than the first.
* The Lost City of Z from ''{{Conduit 2}}''.
* ''VideoGame/DonkeyKongCountry 2'' has a Lost World area that is filled with several types of fauna and it isn't found anywhere else on the island. K. Rool is found in an ancient temple of sorts and defeating him sends him flying into the center of the light the temple is radiating, causing the Lost World to implode and sink the island.
** The 3rd game has a lost world hidden in an island that is underwater and rises when you reveal it. However, the environment is nothing more than a mountainside with barren forests and a lake.
[[/folder]]

[[folder:Webcomics]]
* Zeetha of ''Webcomic/GirlGenius'' is a native of the Lost City of Skifander. Unfortunately, she was ill during the journey from Skifander to Europa, and [[http://www.girlgeniusonline.com/comic.php?date=20041103 doesn't remember the way back]], and everyone else who might have a clue seems to be dead. Sometimes at Zeetha's hands.
* ''Webcomic/SluggyFreelance'' has [[http://sluggy.com/comics/archives/daily/091228 The Valley That Time Forgot Lost In The Center Of The Earth]], which seems to be populated entirely by MoleMen and mole-man eating dinosaurs. The "center of the earth" thing is just a name, though (it's actually a few hundred miles from the earth's core), as is the "valley" part (it's technically a cavern). The "that time forgot" part is literally true, however.
-->'''Father Time:''' I forget nothing! There's an occasional typographical error in temporal accounting but . . . ''Dinosaurs?'' Are those '''''DINOSAURS!?!''''' ''Someone get me temporal accounting! Stat!''
[[/folder]]

[[folder:Western Animation]]
* The ChristmasSpecial ''Rudolph's Shiny New Year'' features a few variations of this trope in the Archipelago of Last Years. Where the old AnthropomorphicPersonification of the year goes to retire, they choose an island to live in and TimeStandsStill for everyone in that island. The island where One Million B.C. lives is {{Prehistoria}} of course, and a YeOldenDays year lives on a MagicalLand.
* Subverted a bit in an episode of ''WesternAnimation/DuckTales'' where the heroes find a Lost World region full of dinosaurs. However, not only do they escape it, but they have its location definitely recorded and make it an one of a kind of wildlife tourist attraction.
* The episode "{{Tarzan}} and the Knights of Nimmr" of the 1970s Saturday morning cartoon ''Tarzan, Lord of the Jungle'' is loosely based on the book ''Tarzan, Lord of the Jungle'' (the setting was largely retained, but the characters and story were replaced with original characters). The two cities were merged into the single city of Nimmr, which had just been discovered by a balloonist at the beginning of the story.
* ''{{Superfriends}}'' (1973-74) episode "The Mysterious Moles". Deep under the earth is the Bottomless Cave: a gigantic cavern filled with plants, lakes and dinosaurs.
* ''WesternAnimation/DinoBoy'', aka ''Dino Boy in the Lost Valley'', which aired along with ''WesternAnimation/SpaceGhost''. The title valley had cavemen, dinosaurs and other prehistoric creatures, and several lost civilizations.
* Kong Island in ''WesternAnimation/KongTheAnimatedSeries'' had dinosaurs, mammoths, an evil god with a harpy for a minion and the big ape himself. One of the episodes dealt with the origin of the island due to a time vortex caused by said evil god.
* In the ''WesternAnimation/{{Futurama}}'' episode "Fun on a Bun", Fry falls into a hole in a German glacier and discovers a secret tribe of Neanderthals, along with wooly mammoths, saber-tooth tigers and giant sloths.
* ''WesternAnimation/BatmanTheBraveAndTheBold'': Dinosaur Island features in "Terror on Dinosaur Island!", "Revenge of the Reach!" and "Four Star Spectacular!".
[[/folder]]

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