->''"First there was the collapse of civilization... anarchy, genocide, starvation... then we got ThePlague."''
-->-- OpeningNarration, ''Film/{{Cyborg 1989}}''

Long ago in the kingdom of [[MagicalLand Troperia]], a great disaster swept through the land. Many lives were lost and, to this day, no one knows what caused the event that has come to be known only as the Cataclysm. Some say that the members of an [[AncientConspiracy ancient society with mysterious, unknown goals were behind it]]. Others say that [[GovernmentConspiracy the powers that govern the people are hiding something]]. No one is completely sure how or why the Cataclysm came to pass, but [[OmnicidalManiac (almost)]] all can agree: the world would be better off if the Cataclysm never came to repeat itself...

... A typical use of the Cataclysm Backstory trope.

Often used in {{Fantasy}} works, a Cataclysm Backstory is a trope that can easily set up the events of a story, or possibly the entire setting itself. It's very common in {{dystopia}} works and often used in stories that take place AfterTheEnd. Cataclysm Backstory can be used in many different ways. It can sometimes provide a touch of mystery to any work, only being mentioned every now and then and possibly kept unexplained until much later in the story [[PlotHole (if it's ever explained at all)]]. If done well, the Cataclysm Backstory in question will be deeply tied in with the events of the plot and explained in detail. If done poorly, it will be used as an easy way of filling any given PlotHole (i.e. Where did that HumongousMecha come from? It was revealed during the Cataclysm). It can also explain bits of technology more advanced than the general cultural level of the society depicted; whatever it was, it was something the survived the Cataclysm.

Contrast FirstEpisodeSpoiler. Compare GreatOffscreenWar.


[[folder:Anime and Manga]]
* ''Anime/GuiltyCrown'' has Lost Christmas, a well-done case where [[TheVirus the Apocalypse Virus]] was released. The first two minutes after the opening of episode one are used to explain how Lost Christmas caused Japan to clamor for help from outside governments in order to keep the virus under control, sacrificing their independence in exchange for stability and setting up the events of the main series ten years later. It goes a lot deeper than that, though. [[spoiler: Episode 11 reveals that a small group of people ''intentionally'' released the virus.]]
* ''Literature/DemonCityShinjuku''. Levih Rah kills his opponent Genichirou and causes an earthquake, devastating the Shinjuku area of Tokyo and leaving it a demon-haunted ruin. Ten years later Genichirou's son, Kyouya Izayoi, must enter Shinjuku and stop Levih Rah from performing a ritual that will allow the demons to conquer the rest of Tokyo and the Earth.
* ''Anime/TheBigO''. Forty years earlier an unknown disaster wiped out human civilization. Only those within the main city and its surrounding landscape remain, but none can remember what happened on that day. It's heavily implied that [[spoiler:''nothing'' existed before that point; that everyone is either a robot or a [[TomatoInTheMirror clone]], what few "memories" remain are simulated, and the city itself is an artificial construct. If the whole setting isn't actually InsideAComputerSystem and everyone is a program... But the GainaxEnding was doing its best to out-do EVA anyway]].
* The Hydrus Beta supernova shockwave that very nearly wiped out humanity 200 years ago in ''Anime/StellviaOfTheUniverse''.
* In ''Manga/{{Akira}}'', the Fall of Tokyo, triggered by the awakening of the title character's incredible psionic abilities.
* ''Anime/CowboyBebop'' has the Gate Disaster, which left Earth a ruin that is constantly bombarded by asteroids. Several one-off characters are connected to it, as well as [[spoiler: Faye]].
* ''Anime/NeonGenesisEvangelion'' gives us Second Impact, a disaster which destroyed Antarctica, caused worldwide flooding and wars, and ended up killing off half of mankind. It's attributed to a meteorite hitting Antarctica, but it was actually caused by [[OmniscientCouncilOfVagueness Seele]] experimenting with and waking [[EldritchAbomination Adam]], who lay dormant there. By the time the story starts, humanity is just starting to return to normal.
* ''Manga/PandoraHearts'' has the Tragedy of Sablier: a hundred years ago, the former capital was thrown into [[EldritchLocation the Abyss]] by [[BadassFamily the Baskervilles]]. In present time, the Baskervilles return and send the main character, [[GuileHero Oz,]] into the Abyss for a crime he knows nothing of, prompting him to investigate their true identity. As it turns out, most of the cast is closely related to the Tragedy. [[spoiler:It has a lot to do with TimeTravel.]] The whole truth is eventually revealed via [[WhamEpisode several chapters]] of [[WholeEpisodeFlashback flashbacks]].
* The [[DetonationMoon Heaven's Fall]] disaster as a result of the GreatOffscreenWar 15 years prior in ''Anime/AldnoahZero'' sets up for the current state of the world.
* The ''Anime/TekkamanBlade II'' OVA has the Prague Black September, a revolt of "Primary Tekkamen" (humans partially transformed by the alien Radam to gain armored bodies but not offensive powers; they were fighting discrimination from "normal" humans) that was put down with the use of nuclear weapons. Only one major character lacks ties to the event, and one character has frequent flashbacks to the burning city. Also, it happened in the wake of an alien invasion that nearly wiped out humanity.
* In ''Webcomic/{{Kubera}}'', all the sura clans suddenly went to war with the gods around the time Leez was born. Entire planets were destroyed and [[HalfHumanHybrid Halfs]] got caught up in [[FisherKing emotional resonance]] and went berserk as a result. Bonus points for the event actually being referred to as the Cataclysm.
* ''Anime/DeadmanWonderland'' has the Great Tokyo Earthquake, also known as the Red Hole, a massive 11.4 quake that occurred on April 4th, 2014. It caused [[http://vignette4.wikia.nocookie.net/deadmanwonderland/images/5/53/Great_Tokyo_Earthquake_map_anime_.png/revision/latest?cb=20110708142026 most of Tokyo to sink]], with 148,000 people dead or missing, and a few were granted [[BloodyMurder Branches of Sin]]. In 2017, the titular prison/amusement park was built to bring in tourists as part of the Tokyo Recovery Project. [[spoiler: In reality, the earthquake was Shiro/the Wretched Egg's failed attempt to [[SuicidalCosmicTemperTantrum kill herself]].]]

[[folder: Comic Books]]
* ''ComicBook/{{Reyn}}'' has the aptly titled Great Cataclysm, a devastating event that nearly destroyed all of humanity. Issue 9 fully explains how the Cataclysm started, and that [[BigBad Brother M'Thall]] caused it.

[[folder: Fan Fiction]]
* ''Fanfic/CodeGeassMegiddo'' has Operation Nero, also known as the Devastation of Japan. Realizing they're losing the war and to ensure the territory won't fall into enemy hands, Prince Schneizel orders all the reserves of [[{{Unobtanium}} Sakuradite]] running underneath Area 11 to be detonated. This results in a series of explosions, giant earthquakes, and volcanic eruptions before one last explosion engulfs the entire archipelago. 130 million people [[WeHaveReserves from both sides]] are killed, Japan is rendered an uninhabitable wasteland, and most of the Japanese race is wiped out. And all of this happens [[DownerBeginning in the first chapter]]. The story itself takes place [[TimeSkip eight years later]].

* Peter Greenaway's {{Mockumentary}} ''The Falls'' is about how people were changed by the "Violent Unknown Event".

* Literature/TheSevenRealmsSeries gives us The Breaking. At first kept very ambiguous, it's eventually explained (in much detail) that many millennia ago, The Demon King kidnapped Princess Hanalea and subsequently performed an act of dark magic that caused a series of natural disasters to sweep the whole of the Seven Realms. Unluckily for him, Hanalea eventually brought him down. [[spoiler:Or so the people come to believe...]] Anyway, fast forward ten thousand years, and street rat Han Alister gets a hold of the Demon King's amulet.
* The Sixty Minute War in ''Literature/MortalEngines''.
* ''Literature/TheHungerGames:'' We never really find out what killed most of humanity and brought about the founding of Panem (though there seem to be lingering environmental consequences). We gradually learn a bit more about the [[GreatOffscreenWar more recent "Dark Days"]] when the Districts rose in (unsuccessful) rebellion against the Capitol, resulting in the institution of the Hunger Games.
* Of the "no one knows" variety in ''Literature/{{Divergent}}'', something has caused Chicago to isolate itself from the rest of the world, turning the society into the five virtue-based factions in the story.
* The Doom of Valyria in ''Literature/ASongOfIceAndFire.''
* ''Franchise/TheWitcher'' series had the Conjunction of the Spheres, which occurred several centuries prior to the saga and brought hordes of chtonic monsters into the world, where they thrived on a healthy human diet. The eponymous witchers (superhuman monster hunters) were invented to protect the local humanity from these monsters, though they've been so efficient over the centuries that their existence is almost obsolete by the time the books takes place, as there are very few monsters for them left to hunt.
* The nuclear catastrophe in Tatyana Tolstaya's novel ''Kys'', which had set the world into a weird state the inhabitants feel natural.
* ''Literature/TheWheelOfTime'' has the Breaking of the World about 3,000 years before the bulk of the series begins, which finally pushed civilisation from advanced to pseudo-medieval.
* ''Literature/HeraldsOfValdemar'': The [[WorldWreckingWave magical Cataclysm]] that occurred 3,000 years in the past of the main story is alluded to in several places but not explored in detail until the "Mage Wars" trilogy, which establishes the necessary details to seed the plot for the "Mage Storms", which involves the return of said Cataclysm.
* There are several Cataclysms in the background of ''Literature/TheLordOfTheRings'', most notably the sinkings of Beleriand and Númenor, which led to the decline of the Elves and the Dúnedain respectively.
* Creator/VladimirVasilyev's ''The Treasure of the Kapitana'' takes place eight centuries after something called the Catastrophe. Despite the fact that the people of the world know exactly ''when'' it took place (they restarted the [[AlternativeCalendar calendar]] to mark the event), they have no idea what wiped out the Ancients and threw civilization back. By the time of the events of the book, the new Middle Ages have arisen. The ending makes vague references that it was the [[spoiler:lack of magic]] that resulted in the Catastrophe but fails to reveal anything of consequence. For some strange reason, the new civilization refers to places and nations using their ancient names, usually dating back to Greco-Roman times. This can confuse some readers wondering what the hell the Euxine Sea is (it's what the Greeks called the Black Sea, and the Brits continued to use the Greek name until the 18th century).
* Creator/SergeyLukyanenko's ''Outpost'' SharedUniverse is focused on the world of Centrum, formerly the [[ExactlyWhatItSaysOnTheTin center]] of an advanced interstellar civilization with portals linking many worlds, including Earth. Then a genetically-engineered bacterium was unleashed on Centrum that consumed all petroleum and petroleum-based products (including plastics), collapsing their civilization and throwing it back to the level of the early-to-mid 20th century. And the bacterium is still around, preventing oil and plastics from being imported from other worlds. Fortunately, the bacterium doesn't appear to be able to survive portal travel, so the "plague" is limited to Centrum.
* In a number of chronologically earlier books of ''Literature/TheHistoryOfTheGalaxy'' series, some characters wonder how a large area of space that has become known as the Sleeve of Emptiness formed. The area is noticeable against the backdrop of the rest of the galaxy, because it is a large stretch of space without any visible stars. Later on, expeditions are mounted to the area, which discover that all the stars of the Sleeve of Emptiness have inexplicably exploded about 3 million years ago, leaving behind charred remains of their planets, still circling what's left of the stars. Furthermore, alien ruins and artifacts are found on those worlds. It's not until later that the truth is discovered and made public. Apparently, the area used to be home to several star-faring races. Unlike humanity, they never invented portable hyperdrives and relied on a static PortalNetwork for intersystem travel. This proves to be their undoing, when they spot a large swarm of ancient spaceborne creatures dubbed "Forerunners" moving in their direction, attracted by starlight. The Forerunners are clumps of protomatter, whose origins are generally stated to be "the first lifeforms to appear in the universe" (except for one novel that claims that they were created by a powerful EnergyBeing and are indirectly responsible for all biological life in the galaxy). Forerunners have animal-level intelligence, and their only motivation is [[HordeOfAlienLocust consuming matter (any solid matter will do)]] and reproducing (via a mitosis-like process). Without FTL travel, the ancient races had to find other means of surviving. The [[InsectoidAliens Insects]] and the [[StarfishAliens Logrians]] chose to flee en masse via the portals into [[HumanAlien Harammin]] territory only to be enslaved by them (who then used Logrian ingenuity and Insect labor force to surround their star cluster with a shell of gravity-bending generators that hid the cluster from view (thus removing themselves from the Forerunners' menu). Some Insects attempted to build a DysonSphere in order to hide inside it, but they haven't managed to complete it in time and fled. The only race that chose to stay and fight were the [[FishPeople Delphons]], who knew that, unless they were stopped, the Forerunners would cut a swath through their part of the galaxy, consuming all planets in their path, including those with nascent life (including a certain blue-green world with primitive anthropoids). Their only means of fighting the swarm was to trigger a nova-like explosion in their stars, which they used whenever the swarm approached. By the time the swarm was finally stopped, the Delphons had detonated all their stars and went extinct along with the Forerunners.

[[folder:Live-Action TV]]
* ''Series/{{Revolution}}'': The premise of the story is that a worldwide blackout occurred and stays in effect for 15 years. As the first season goes on, more on the backstory is revealed. [[spoiler:The power was shut down by electricity absorbing nanites that were created by Rachel Matheson and Ben Matheson. Randall Flynn, representative of the Department of Defense, was happy to fund their project. From a secret location in Colorado known as the Tower, Randall activated the nanites in Afghanistan in response to his son's death. Unfortunately, the nanites got out of control and spread throughout the world. Aaron Pittman is able to find out that the nanites did not go out of control by accident. It seems that someone deliberately programmed them to spread out of Afghanistan, but there is no way of knowing who could have done that and why.]]
* ''Series/ThatMitchellAndWebbLook'' had a series of game-show skits set in the post-cataclysmic CrapsackWorld that remains after "the event." The details are left sketchy for added humor ([[NothingIsScarier and horror]]), but the contestant and viewers are continually advised to "remain indoors" and to do their best not to think about "the event."
* The [[GreatOffscreenWar Last Great Time War]] in the revived series of ''Series/DoctorWho''. The Doctor's emotional scars are behind much of their character development, and many episodes revolve around the after effects of the War (displaced civilizations, occasional surviving Daleks, etc).

[[folder: Mythology and Religion]]
* The [[http://en.wikipedia.org/wiki/Fall_of_Man Fall of Man]] in Abrahamic faith. Also TheGreatFlood.

* "The Withering" in ''Radio/{{Nebulous}}''.

[[folder:Tabletop Games]]
* ''TabletopGame/{{Greyhawk}}'' has the Twin Cataclysms: the Invoked Devastation and the Rain of Colorless Fire.
* The Day of Mourning that played a big part in ending the Last War in ''TabletopGame/{{Eberron}}''. No one knows what caused it or which of the Five Nations was responsible, but we know it wiped Cyre off the map and rendered it an inhospitable wasteland known as the Mournland.
* ''Literature/{{Dragonlance}}'' has the Cataclysm, which went down when the Kingpriest of Istar demanded to be given godlike powers to eradicate evil from the world (more specifically, to genocide the ogre races and relocate the dwarves and kender). The gods were not pleased, and punished him by wiping the city of Istar off the face of Krynn, creating what has since been called the Blood Sea of Istar due to the thick red soil churned up by the sea creating a blood-like appearance; as well as splitting apart the Kingdom of Ergoth, messing life up for several cities (one inland city found itself becoming a coastal city because of a new inland sea, and a port city found itself becoming an inland city surrounded by plains), and outright destroying several more cities including Xak Tsarosk.
* ''TabletopGame/{{Exalted}}'' has two consecutive ones in the form of the Great Contagion (wiped out the majority of all life) and Balorian Crusade (dissolved a significant portion of the world.
** Autochthonia has a relatively small scale version in the destruction of the patropolis Ixut, which kickstarted the [[GreatOffscreenWar Elemental War]].
* In ''TabletopGame/BladesInTheDark'', About 850 years ago, the old world was shattered by an unspecified cataclysm that made it impossible for spirits of the deceased to pass on to the afterlife, creating a staggering number of ghosts. It had also caused continent-shattering earthquakes across Akoros, turned the ocean water into black ink, released colossal leviathans into the seas, and, most importantly, almost extinguished the sun, plunging the the world into a permanent darkness.

[[folder:Video Games]]
* The Black Beast rampaging all over the world in ''VideoGame/BlazBlue''.
* ''VideoGame/{{Warcraft}}''[='s=] Sundering is this, although the more recent event that is actually called the Cataclysm is not.
* ''VideoGame/WhiteKnightChronicles'' gives us, well, the Cataclysm. It happened about seventeen years before the start of the story and it's only mentioned a few times in the entire series, but it's the basic explanation for how the [[LostTechnology Yshrenian]] [[HumongousMecha Knights]] [[spoiler:and the heroes as babies]] were revealed. No real explanation is given, but it's heavily implied to be because [[BecauseDestinySaysSo it was simply time for Emperor Madoras to rear his ugly head again, and for him to be defeated]].
* The Collapse, a [[CrypticBackgroundReference oft-mentioned but never-explained]] cataclysm that separates ''VideoGame/TheLongestJourney'' and ''VideoGame/DreamfallTheLongestJourney''.
* Whatever destroyed the Prothean civilization in ''VideoGame/{{Mass Effect|1}}''. [[spoiler:Actually, an invasion by the extragalactic genocidal race of giant sentient machines known as the Reapers. And this is far from the first time they've done this.]]
* ''Franchise/TheLegendOfZelda'':
** Hinted at in ''VideoGame/TheLegendOfZeldaSkywardSword'', and, by extension, the rest of the ''[[Franchise/TheLegendOfZelda Zelda]]'' series to which it is a prequel. The cataclysm in question was invasion by demons, and before it, there was a civilization of sapient robots with technology to put modern Earth to shame. After it, the setting MedievalEuropeanFantasy with a bit of LostTechnology scattered here and there, [[MedievalStasis which then becomes the status quo for thousands of years]].
** Averted in ''VideoGame/TheLegendOfZeldaTheWindWaker''. The game's opening tells of a "Legendary Kingdom" that fell to a great evil - but what fate eventually befell it, no one knows. It turns out that the island cities of the Great Sea are the descendants of that doomed kingdom - but no one even remembers the cataclysm as a historical event, only as a legend.
** ''VideoGame/TheLegendOfZeldaBreathOfTheWild'' takes place 100 years after Calamity Ganon ravaged the land. The Hylians knew it was coming and tried their best to prepare for it, but the Calamity took over the mechanical army they'd unearthed and turned it against them. The Kingdom of Hyrule is all but a non-entity, with only a few scattered villages remaining. The only thing that stopped Ganon from wiping out ''everything'' was Princess Zelda sealing him in Hyrule Castle, which she continues to do until the game starts, but she can't keep it up forever...
* ''VideoGame/{{Fallout}}'' takes place in the aftermath of the Great War, a nuclear apocalypse that created the game's ScavengerWorld.
* ''Franchise/DragonAge'':
** The defilement of the Golden City by Tevinter Magisters, which gave rise to the [[GreatOffscreenWar First Blight]] and placed the future generations into constant danger of a Darkspawn invasion. At least, so the Chantry would have us believe. ''Some'' calamity instigated the Darkspawn, but the truth has been [[RiddleForTheAges lost to time.]]
** According to the sequels, the Chantry's version is actually partly true, but the Tevinter Magisters who were supposedly the ones who corrupted the Golden City (giving rise to the Darkspawn) claim that they found the city already corrupted.
** There's also the fall of Arlathan, the ancient civilisation of the elves before the humans [[EnslavedElves enslaved them.]] This is thought to be the result of Fen'Harel, a trickster god known as the Dread Wolf, [[HaveYouSeenMyGod sealing away the other elven gods.]] The third game drops several hints as to what really happened before spelling it out in ''Trespasser''. [[spoiler: Solas, who IS Fen'Harel, created the Veil itself to imprison the other gods (bar the almost-dead Mythal) because they were a threat to the world.]]
* This is the case in ''VideoGame/DarkSouls''. The First Flame, the source of all fire and light and disparity in the world is on the verge of dying. This is actually the second time this has happened. The first time happened about 1,000 years before the main events of the game, and caused the loss of the two most proactive Lords, Gwyn and Izalith, the complete downfall of the city of Izalith, unleashed demons onto the world and set in motion the events that caused the gods to abandon Anor Londo.
* Many of the plotlines in the ''VideoGame/AceCombat'' series can be traced back to the Ulysses 1994XF04 asteroid impact in 1999. Most of the gigantic superweapons involved in later Strangereal wars (Usean Stonehenge, Erusian Megalith, Estovakian Chandelier) were originally built to protect their respective nations from Ulysses' fragments, and at least two conflicts ([[VideoGame/AceCombat04ShatteredSkies Usean]] and [[VideoGame/AceCombat6FiresOfLiberation Anean Continental Wars]]) were immediate consequences of the devastation caused by the debris that did get through. Additionally, the Osean-Yuktobanian space station ''Arkbird'' from ''VideoGame/{{Ace Combat 5|TheUnsungWar}}'' was originally commissioned to clean up the Ulysses debris still floating in orbit.
* The Silence serves as this in ''VideoGame/HeroesOfMightAndMagic I''-''III'' and ''VideoGame/MightAndMagic VI''-''VIII''. In the ''Heroes'' series, it is a CrypticBackgroundReference to the point that it isn't even explicitly indicated to be this trope, while the ''Might & Magic'' games goes into more detail, revealing early on ''what'' the Silence was (the colonial masters of the planet, the Ancients, withdrew for unknown reasons, and the loss of inter-planetary travel lead to a collapse of high-technological civilization), and in the end-games ''why'' it happened ([[spoiler:the [[PlanetLooters Kreegan]] attack on the Ancient civilization damaged Ancient infrastructure across the local galactic arm, leading to a loss of contact with many of their colonies. The Ancients would have rebuilt the links, except they're still busy fighting the Kreegan]]).
* The [[spoiler:Fall of Cocoon]] that took place in the end of ''VideoGame/FinalFantasyXIII'' shapes the world to a great extent in ''VideoGame/FinalFantasyXIII2''.
* The Keyblade War from ''Franchise/KingdomHearts''. Apart from anything else, the numerous tiny and largely cut off from one another worlds the series takes place on used to all be one planet prior to the War.
* The Elf Wars, set between the ''VideoGame/MegaManX'' and ''VideoGame/MegaManZero'' series. The conflict lasts only four years, but the casualties that are tallied reach up to approximately 60% humans and 90% Reploids.
* The Crusades in ''VideoGame/GuiltyGear'', a bloody altercation wherein the Gears, led by the [[MonsterLord Commander Gear]] Justice, TurnedAgainstTheirMasters and set forth to KillAllHumans. Beginning in the year 2074 with Justice's revolt, the war lasted over a century, only finally ending in 2175 when [[UsefulNotes/TheKnightsTemplar the Holy Order]] [[SealedEvilInACan sealed away Justice in an extradimensional prison]]. It's unknown how widespread the damage was, but America--the country responsible for starting the Gear Project--[[FallenStatesOfAmerica has fallen into ruin and is now simply known as A Country]] (Sol's stage in the original game [[SceneryGorn is that of a]] {{ruin|sOfTheModernAge}}ed New York City, complete with [[MonumentalDamage the severed head of the Statue of Liberty]]), London was once at risk of being razed by [[{{Kaiju}} a Megadeth-class Gear called Hydra]], and, in one of the very first acts of war, ''[[TheTokyoFireball the entire country of Japan was obliterated]]'', with the surviving Japanese being relegated to colonies and classified as "national treasures." What's worse, [[ForWantOfANail there exists]] [[BadFuture a timeline]] [[ForWantOfANail where]] [[spoiler:I-No [[TimeTravel goes back in time]] and [[ForTheEvulz manipulates events at a whim]], leading to the death of Ky Kiske at the Battle of Rome in 2173. This is treated as a ''worldwide'' DespairEventHorizon and causes the Crusades to extend at least into 2183, with Justice's daughter Dizzy taking charge of the Gears in her fallen mother's place]]. It's implied the fallout here is much, ''much'' worse.
* Permeates ''VideoGame/SkiesOfArcadia''. About a thousand years ago, the world's six Moons suddenly dropped a bunch of meteors on the planet below, pummeling the ancient civilizations into the stone age in an event called the Rains of Destruction. By the start of the game, humanity has only just about recovered to the equivalent of Age of Discovery technology. [[spoiler:And there are factions who are trying to make the Rains fall again...]]
* In the expansion of ''VideoGame/SidMeiersAlphaCentauri'', it's revealed that the planet called Alpha Centauri/Chiron is actually an ancient experiment on planetary-scale artificial sentience using genetically-engineered ecosystems called "Manifold Six", created by a race of {{Precursors}}. 100 million years ago, another Manifold, Tau Ceti, gained planet-wide sentience (called "Flowering") resulting in a massive psionic disruption which annihilated three systems and broke the back of the Progenitor civilization. The surviving aliens have split into two factions, the Manifold Caretakers who are determined to locate and protect the remaining Manifolds so they remain in their dormant state, and the Manifold Usurpers who apparently didn't learn their lesson and are trying to find another Manifold and activate it so they can achieve godhood. Their views are summed up in these quotes:
--> "Risks of Flowering: considerable. But rewards of godhood: who can measure?" -- Usurper Judaa Marr, ''Courage : To Question''
--> "Tau Ceti Flowering: Horrors visited upon neighboring systems must never be repeated. Therefore: if it means the end of our evolution as a species, so be it." -- Caretaker Lular H'minee, ''Sacrifice : Life''
* In the ''VideoGame/KisekiSeries'', an event known as the "Great Collapse" took place 1,200 years ago, wiping out the ancient Zemurian Civilization and leaving a lot of highly advanced technology behind. This LostTechnology is the main reason why the "Orbal Revolution" happened, advancing the technology from a [[TheMiddleAges Medieval]] to {{Steampunk}} level.
* ''VideoGame/MarsWarLogs'' and its sequel ''The Technomancer'' both take place on Mars 70 years after its colonies were cut off from Earth in an event known as "The Turmoil." The Turmoil also made the Martian Atmosphere incapable of filtering out solar radiation.
* [[BigBlackout The Datacide]] in ''[[VideoGame/SteelBattalion Steel Battalion: Heavy Armor]]'', during which all of Earth's microprocessors were destroyed by a silicon eating microbe. Mankind managed to rebuild and is now on the technology level of the 1940s.
* ''VideoGame/ChildrenOfADeadEarth'' has [[ExactlyWhatItSaysOnTheTin The Cataclysm]], a conflict marked by weaponized geoengineering which rendered Earth uninhabitable and reduced the human population so much that, over 200 years later, there are still fewer than two billion humans across the entire solar system.

[[folder:Web Original]]
* ''Roleplay/OpenBlue'' has two: first was the fall of the [[{{Precursors}} Iormunean Imperium]] 1200 years ago, which is directly responsible for the existence of at least one major power in the setting, and indirectly responsible for another. The second was the more recent Disaster of Nations 3 months ago, which is responsible for the weakening of the world superpowers, and the return of the Pirate Lords to power.

[[folder:Western Animation]]
* The Land of Ooo in ''WesternAnimation/AdventureTime'' was implied to be our world AfterTheEnd, with mentions of a [[UsefulNotes/NuclearWeapons "Great Mushroom War."]] This explains why there are electronics in an otherwise MedievalStasis fantasy world, and the presence of RuinsOfTheModernAge. Season 5 finally just flat out confirms that the event was a thermonuclear war.
* ''WesternAnimation/GeneratorRex'': A massive FreakLabAccident infests the entire world with [[{{Nanomachines}} nanites]], which cause extreme mutation on much of the population. Most of the major characters are ultimately revealed to be somehow connected to the event.

* Western civilization had a handful of these, but none have been more prominent than the fall of the Roman Empire in 476 A.D., widely considered the end of the Ancient World.