History Main / UnspecifiedApocalypse

->''"I have ideas [about the cause of the zombie plague]...but it's nothing set in stone because I never plan on writing it. So yes...I do know...kind of."''
-->-- '''Robert Kirkman''' on the origins of the zombie apocalypse in ''ComicBook/TheWalkingDead''

* Many timelines of the distant future either culminating in the ultimate fates of the Earth and the Solar System (which will eventually be destroyed by the Sun's aging into a red giant and subsequent death throes) and/or the ultimate fate of the universe (which will most likely be due to the universe's continued expansion gradually accelerating over time until it finally gets reduced to a cold, dark, empty void) will often tend to leave out the more imminent ultimate fate of humans altogether.

* ''WesternAnimation/LoveDeathAndRobots'': In "[[Recap/LoveDeathAndRobotsThreeRobots Three Robots]]", there are conflicting reports as to why humanity went extinct. A nuclear holocaust is proposed first, and 11-45-G's research suggests it was environmental catastrophe brought about by environmental degradation and climate change. The cats claim ''they'' did it because humanity [[YouHaveOutlivedYourUsefulness had ceased to be of any use to them once they were given thumbs]], but [[UnreliableExpositor this isn't reliable]] when the same cats are trying to take the robots hostage by exploiting their ignorance.

* ''ComicBook/TheWalkingDead'': A smaller example. We know that the dead walking again caused the end, but why it started happening is never really discussed. WordOfGod has even said that [[RiddleForTheAges he has no plans to explore the reasons either]].

* ''Film/LogansRun'': What caused the end is never mentioned, in contrast to the novel, where overpopulation is stated as the cause for the dystopian society.

-->'''Host:''' Multiple choice: Which of Shakespeare's three plays is now thought to be prophetic of the Event? Is it A) Paracleese, B) Symbolene, or C) Boeing-Boeing?\\

* In ''Manga/{{Saikano}}'', there's a war going on with an unspecified country or countries, also the world is dying for some reason, [[spoiler: and it's actually destroyed in the ending]]. But no details are given.
* ''Manga/DriftingClassroom'': The story revolves around a Tokyo elementary school that is somehow transported into a BadFuture where all of Japan, and presumably the rest of the world, is a desert wasteland inhabited by nothing except a sparse population of hideous mutants. According to the mutants, as well as an old film reel they have, this was caused by overpopulation, environmental damage and resource depletion, but not in any detail, and the source of the mutations is never explained, other than a vague story about humans just suddenly starting to give birth to them at some point. It's made even more confusing when it's revealed that a strange type of fungus that shows up after a flood begins turning any of the kids that eats it into the same kind of mutants.

* During the original ''ComicBook/{{Kamandi}}'' run, the "Great Disaster" that devastated the world was explicitly stated to not be a nuclear war, but otherwise was never elaborated on. Later revisits to the setting would retcon it to be a war after all while ''ComicBook/CountdownToFinalCrisis'' had it be a plague from the future.

* ''WesternAnimation/AtlantisTheLostEmpire'': Whatever exploded that caused the cataclysm that destroyed (most of) Atlantis and buried the part that was protected by the shield. All that is absolutely sure is that one Atlantean looks at another and yells out "YouFool! You destroyed us all!" before they both perish in the tidal wave that resulted from the explosion, but ''what'' did ''that'' will be forever unknown.
** Some dialogue later in the film strongly implies that it was something to do with the mysterious, probably-sentient source of their civilisation's MagiTek reacting badly to being used as a weapon of mass destruction, but who the Atlanteans were at war with and why they weren't satisfied with their already-ridiculous technological edge over anyone else on Earth at the time is never explained, and the sequel film and spin-off series that might have gone on to do so [[StillbornFranchise never materialised]].
* ''WesternAnimation/{{Nine}}'': It is heavily implied some sort of war in an Alternate Earth wiped out humanity, leaving our creations to inherit the Earth.

* ''Franchise/PlanetOfTheApes'': The details involving the nuclear war in the original series are never explored. All that matters is that the apes inherited the world.
* ''Film/StakeLand'' involves a vampire apocalypse devastating North America (and the rest of the world including the Middle East, except apparently for the northern-most parts of Canada) and two men heading towards this "New Eden". There is never any specific information about where the vampires came from or how they came to exist.

* ''Film/ChildrenOfMen'': It is never revealed what caused the SterilityPlague that resulted in the ChildlessDystopia and no-one seems to know what caused it in-universe as well. There are also quite a few mentions of {{Noodle Incident}}s in [[BigApplesauce New York]] and UsefulNotes/{{Madrid}} that suggest that the rest of the world is being turned into nuclear wastelands or lawless war zones, especially if you believe the government propaganda.
* ''Film/TheBookOfEli'' has Creator/DenzelWashington in a world decimated for an unknown reason (heavily implied to be nuclear warfare). A number of people who were alive at the time of "The Flash" still suffer burns, scars, and blindness from the event ([[spoiler:including him]]).
* ''Film/{{Pandorum}}'' starts with a SleeperShip called the ''Elysium'' travelling towards a distant planet for colonisation when they receive a message from Earth telling that they are all that remains of the human race. Following flashbacks mention that the ''Elysium'' tried to contact and then find Earth, but it had been completely vaporised somehow, and no theory is of help at the current moment in the story.
* ''Film/ShaunOfTheDead'': There are multiple reasons given for the ZombieApocalypse, including a new super-flu, GM food, radiation from a downed satellite in reference to ''Film/NightOfTheLivingDead1968'' and it is intentionally vague to which one is the true cause. In the denouement, a news anchor starts saying that scientists have now determined the cause to be... and is cut off when someone changes the channel.
* ''Film/TheDayAfter'': While it's not ''completely'' unspecified (WorldWarThree erupting), there is one detail that is ''very'' specific, which various characters ask throughout the film for the sake of trying to feel better and that is deemed totally unimportant by the rest: who fired the nukes first, the Russians or the Americans? The reason within the film why the rest don't care is because the world is devastated either way and knowing this just won't fix anything. The reason in RealLife why this goes unmentioned is because the producers wanted to showcase the horrors of nuclear warfare and having the plot pointing fingers would be counter-productive -- this is also the reason why the film was not BackedByThePentagon.
* ''Film/ItComesAtNight'': A mysterious, highly contagious virus of unknown origins led to the collapse of civilization. [[MaybeMagicMaybeMundane Supernatural entities may or may not be involved]]. That’s about the extent of information we get about the apocalypse. The characters themselves aren’t really sure what caused all this or whether [[AmbiguousSituation said supernatural beings even exist]]. All that’s clear is that society is gone, and they have to fight for survival.

* ''The Day'': A group of survivors from an unexplained apocalypse roams the former US, trying to avoid the [[CannibalClan cannibal tribes]] that have sprung up in its wake. There's no discussion of what occurred, with the only thing clear being the society utterly collapsed given the results in the film.
* The world of ''Film/MadMax1'' takes place in an anarchic society, where law and order is next to non-existent and ultra-violent gangs have risen up to rampage against decent people. [[AllThereInTheManual Production documents state that the first movie takes place after a war between Saudi Arabia and Iran, which led to an oil shortage]]. But what happened between the first movie and ''Film/MadMax2TheRoadWarrior''? Things got ''worse''. It is never really explained how the world got to this horrific state, but in [[VideoGame/MadMax2015 the video game]], Max basically says that - as far as he can tell - literally everything that could go wrong ''did'' go wrong, all at once, and consequently nobody really knows which specific catastrophe [[TheLastStraw actually caused the apocalypse]]; the collapse of society, massive wars destroying countries, oceans drying up, super-plagues everywhere, and more.

* In [[Literature/ThePrecipice The Precipice]], a hail of meteors created a number of large craters fifty years before the story proper; it is speculated that this was the source of Superpowers, and it is mentioned that millions died, but in the decades since the world has settled into a kind of normalicy.
* ''Literature/PerdidoStreetStation'' series. The khepri of the Bas-Lag novels fled their native continent ''en masse'' to escape a disaster known as "the Ravening". Whatever it was, it traumatized their kind so completely that none of the survivors of their 25-year sea journey to Bas-Lag ever passed on the details of the catastrophe, or of the ancient khepri culture it destroyed, to their descendants.
* ''Literature/TheRoad''. What brought upon the end of the world is never really stated; theories ranging from asteroid impact to a nuclear war have been brought to the front. Whatever it was, it is of little consequence to the characters, who will be dead anyways at some point as the biosphere is now dead.
-->The clocks stopped at 1:17. A long shear of light and then a series of low concussions.
* ''Literature/TheGiverQuartet''. ''Literature/GatheringBlue'' mentions The Ruin, a recurring event throughout history that has brought humanity to its knees again and again. The last time it happened, it is implied to have been to modern civilization. While ''Gathering'''s, ''Messenger'' and the village that takes in Claire in ''Son'' have regressed to medieval level tech (with a few smackings of SchizoTech and LostTechnology here and there) ''Literature/TheGiver'' (and a few briefly mentioned, but never explored societies) managed to end up with futuristic technology. There is an unspecified society that owns the boats that deliver supplies to the Community that is at least at industrial level, that apparently didn't dip into Sameness, but the series never goes into details about it.
* ''Literature/TheHungerGames''. The event that caused the fall of this world and the rise of Panem is never stated. It is hinted to be some sort of environmental catastrophe though. Whatever it was, for whatever reason, one consequence is that [[ArtisticLicensePhysics planes have to fly low to the ground, since the upper atmosphere is apparently non-existent.]]
* Ford Prefect from ''Literature/TheHitchhikersGuideToTheGalaxy'' is the son of the only survivor of the Collapsing Hrung Disaster on Betelgeuse VII. His father was never able to satisfactorily explain what a "hrung" is, why it had collapsed (or why it chose that planet to do it on), or how he's survived it himself.
* In ''Literature/SimeGen'' the fall of "our" civilization was caused by the mutation that split humanity into the titular Simes and Gens, but what caused the mutation to occur in the first place has no definitive explanation and, according to the authors, will never have a definitive canon explanation, though in character speculation is fair game.
* ''Literature/{{Malevil}}'' has the characters trying to survive in the post-WorldWarThree, nuclear warfare-inflicted chaos that assails the French countryside. At no point it is ever found out ''what'' triggered the nuclear exchange-whether it was a type of FailsafeFailure, flat-out war or insane GeneralRipper-types on both sides pushing the button, the characters speculate a lot but finally agree that this a question that will probably never be answered and holds no importance in light of their current plight.
* ''Literature/TheDayOfTheTriffids'':
** Downplayed. It's clear ''how'' civilization collapsed -- mysterious green flashes drove nearly everyone in the world blind -- but the nature and origin of these things isn't clear. They're alleged to be caused by a malfunctioning KillSat, but this is [[UnreliableExpositor explicitly nothing more than an educated guess on the protagonist's part]].
** The origin of the Triffids themselves is equally unknown -- they simply started growing all over the Earth one day. The theory put forward in the book is that they were engineered by the Soviets, then spread when a plane attempting to smuggle samples to the USA disintegrated at altitude, allowing the wind to spread seeds everywhere. However, this is based on the claims of a single, now dead, person and is again presented as nothing more than a best guess by the narrator.
** The 1956 movie explains away both of the above items to [[CometOfDoom a meteor shower]] and [[CameFromTheSky an explicitly alien plant]]. Whether or not this counts as AdaptationDecay is left to the specific audience member -- they are [[AmericaSavesTheDay far from]] [[KillItWithWater being the only]] changes done in the adaptation.

* ''Literature/TheFutureIsWild'': In the original BBC version, humans go extinct for an unspecified reason at some point before five million years in the future. The American version changes it so they simply left Earth and colonized a new planet. Either way, this lets the work ignore the continuing impact and development of human civilization to focus on the evolution of wildlife and ecosystems.
* Creator/CoryDoctorow's short story (eventually turned into a comic) ''"When Sysadmins Ruled the Earth"'' describes an unspecified apocalypse from the viewpoint of a [[ExactlyWhatItSaysOnTheTin system administrator]], who has to go to work late at night due to a server issue. While there, he gets a call from his wife, who tells him that their infant child has already died from an unspecified cause, and she herself dies while on the phone. Very quickly, the sysadmins lose contact with the rest of the world. Eventually, they manage to re-establish contact with others like them via the still-working Internet and establish an Internet-based government. WordOfGod is that this trope is invoked deliberately, since a regular person is highly unlikely to know the details of a sudden apocalypse and likely wouldn't care anyway. They get an email - purportedly forwarded from Health Canada -- that the whole city’s quarantined because of a biological weapon, but as everything falls apart ''very'' quickly, it's never confirmed.
* Played with in ''Literature/ThePeripheral'' by William Gibson. One half of the story takes place in the future, after "The Jackpot" wiped out a large chunk of humanity, with the survivors — largely rich folks — rebuilding after. A character in the present asks what "The Jackpot" was, and her future contact person eventually explains that it wasn't a singular apocalyptic event so much as various economic, environmental and sociopolitical trends and smaller events (the assassination of the U.S. president, for example) over the course of several decades of decline.
* ''Something'' happened in the distant past of ''Literature/TheDinosaurLords'' that caused the ancient, advanced human society inhabiting Paradise to collapse and [[DaysOfFuturePast regress technologically]]. Ruins and technology of their time is scattered across the land. It’s never revealed what exactly happened, though hints are dropped that [[spoiler:the Gray Angels]] were involved.

* ''Literature/CityOfBones1995'' by Creator/MarthaWells is set a thousand years after a calamity that reduced most of the known world to a ThirstyDesert. The few remaining historic records are from the "Survivor" era when the Waste was new (and [[DeathWorld molten]]). Subverted late in the book, where a new find reveals that the Waste was a [[GodzillaThreshold side effect]] of Ancient humanity's desperate attempt to [[spoiler:hold off an invasion of malevolent spirits from AnotherDimension]].
* In ''Literature/AnUnkindnessOfGhosts'', humanity has gone extinct except for the inhabitants of a GenerationShip. We never learn what happened, especially since plant life and at least some animal life has survived.

* ''Literature/TheWitchOfKnightcharm'': One of the new recruits at an evil WizardingSchool is Janet Yawkly, an Anabaptist who hates violence and clearly is terrified of everything around her. This raises the question in the protagonist's mind of why Yawkly is there in the first place, and while she doesn't say exactly why, it's implied--through her strict use of the past tense when referencing her community--that something horrible happened and destroyed them.

* In ''Literature/{{Dreamsnake}}'', while it's clear it was some sort of nuclear war from the radioactive craters still dotting the landscape, who was fighting and why has been lost to history.

* ''Enforced'' in the ''Series/LifeAfterPeople'' film and series, as it's explicitly stated to be the story of what's left behind ''after'' humanity vanishes, not why/how we disappear.
* ''Series/TheFlipSideOfDominickHide'' had some sort of apocalypse at the end of the 20th century which left most of the planet contaminated with pollution and poison, but it isn't specific as to what did it.
* In ''Series/{{Firefly}}'' vague allusions are made to EarthThatWas, implying that something cataclysmic happened to cause an exodus. Details are absent. The most explanation we're ever given is one version of the show's opening, which simply says that Earth got "used up," and the prologue to the film ''Film/{{Serenity}}'', in which a teacher says Earth could no longer sustain its population.

-->'''Host:''' Multiple choice: Which of Shakesphere's three plays is now thought to be prophetic of the Event? Is it A) Paracleese, B) Symbolene, or C) Boeing-Boeing?\\
'''Sheila:''' ''(buzzes in)'' Is it a trick question?\\

'''Sheila:''' ''<screams and runs out of the room>''\\
'''Host:''' Oh dear oh dear, some horrible memory from The Event no doubt.\\

'''Host:''' Yes indeed; by night, we all get them. Please everyone, remain indoors.
* ''Series/TheFortyFourHundred'': The exact nature of the catastrophe that causes the [[DepopulationBomb near extinction of humanity]] in the future is never revealed. And if a reveal was in the plans, [[CutShort we just never got to see it.]]

[[folder:TabletopGames]]
* The game ''TabletopGame/BaseRaiders'' takes place in a superhero universe Earth where an event simply known as "Ragnarok" made [[TwilightOfTheSupers all of the superheroes and supervillains of the planet simply disappear overnight]]. It must have been something of ''[[CrisisCrossover insane]]'' proportions for this to happen, but if there is anybody on the planet who knows the specifics, they ain't telling. The only thing the player characters care about if that this has left a myriad of secret bases full of comic-book superscience and magic gear lying around ready to be plundered and sold on the black market, justifying the game's angle of "modern-day DungeonCrawling".
* ''TabletopGame/GammaWorld'' from version to version, the events that destroyed the world are different, but for most versions the details remain in the dark.
* '''TabletopGame/{{Numenera}}'' takes plane in "the Ninth World", Earth a billion-plus years in the future after civilization has risen and fallen multiple times, leaving behind a whole lot of weird gadgets (the titular Numenera) and ruins. Not only does nobody knows how any of the previous Worlds fell, nobody is even sure if there were only eight Worlds prior to the "current day".
* ''TabletopGame/{{Paranoia}}'' takes place after something only referred to as the Big Whoops. But, whatever happened, Friend Computer is sure it was caused by [[RedScare evil Communists]]. [[spoiler: Some of the Ultraviolet sections reveal that an asteroid the size of Sheboygan made its way to Earth, causing the Big Whoops. A Russian missile silo mistook the asteroid for a nuclear attack, and The Computer mistook that counter-nuclear attack as an attack by Communists (its information records were damaged, and it could only retrieve 1950's cold war propaganda at the time). They then tell the Gamemaster to use this explanation, come up with another one, or keep changing the backstory, all to keep the players experiencing the setting's trademark Fear and Ignorance.]]
* ''TabletopGame/{{Rifts}}'' is set roughly 300 years after an event called "The Great Cataclysm" or "The Coming of the Rifts" nearly destroyed humanity, and reshaped the world. What's mainly known to people living on Rifts Earth is that political tensions were rising at the time, and it's assumed that some kind of war broke out, though how that lead to the Coming of the Rifts is unknown. Bits and pieces were teased out in the books for years. At present, most of the story is known. The Great Cataclysm was triggered by one South American nation nuking another South American nation on the Winter Solstice at midnight, during a rare planetary alignment. This combination of events, millions of people simultaneously dying when the Earth's magic level was higher than it had been in millennia, caused a chain reaction that nearly destroyed the world. Details are still left out, such as which nation bombed which other nation, and why. But since the cause of the Cataclysm isn't the focus of the game, we'll probably never learn all details.
* ''TabletopGame/DeadReign'' (by the same company that makes ''Rifts'') takes place in a worldwide ZombieApocalypse that was caused by a strange sickness known only as "The Wave" which killed people and made them rise as zombies. What actually caused the wave in the first place is unknown with most survivors not really caring about finding out what happened in favor of trying to survive for another day.

* Whatever destroys the Earth in ''VideoGame/{{Seedship}}'' is never explained. It's very likely that whatever it was also took out the solar system as well, as text in the game refers to Earth's star as "dead". Seeing that the titular ship does have the ability to create successful colonies on non-habitable worlds, which the solar system has plenty of, this is likely the case.
* The ''Final Frontier'' mod for ''[[VideoGame/{{Civilization}} Civilization IV]]'' has all contact with Earth lost, and the game outright states at the beginning that it is likely that something terrible happened to it. [[spoiler: Dialogue in tech quotes hint that Earth was trying to do some sort of transcendence project that went wrong, and destroyed the entire star system.]]
** While the world isn't destroyed in ''VideoGame/CivilizationBeyondEarth'', it's in bad shape after something called the Great Mistake. WordOfGod is deliberately mum on what the Great Mistake was. All we see in images and trailers is widespread poverty and the flooded Pyramids. Some additional material indicates that natural resources are close to being used up, which is why the Seeding missions to other worlds are financed in the first place. The Purity and Supremacy victory conditions involve building a gate to Earth. The Purity-aligned faction strives to build the Exodus Gate, which has refugees from Earth pouring in, requiring them to be settled somewhere. The Supremacy-aligned faction attempts to build the Emancipation Gate (looks pretty much the same), and then sends troops to Earth to engage in some UnwillingRoboticisation.
* ''VideoGame/{{Metro 2033}}'', ''VideoGame/MetroLastLight'' and ''VideoGame/MetroExodus''. What caused the war of 2013? The official website shows that the initial nuclear explosions were in the Middle East and the situation then escalated. Beyond this, all we know is that it was probably between Russia and NATO, but even that is unconfirmed. To the residents of the Metro though, figuring out the facts hardly matter.
* ''VideoGame/EnslavedOdysseyToTheWest'' takes place AfterTheEnd, in the ruins of the modern times. What exactly happened to nearly wipe out humanity is never even discussed, characters mostly focus on continuing their survival and barely question the relics of the past.

* In the ''[[VideoGame/StarSiege Siege]]'' trilogy of games by Creator/{{Dynamix}}, the timeline actually starts with an unexplained apocalypse laying waste to the world and bringing humanity to the brink of extinction before bouncing back AfterTheEnd. Interestingly, no one knows what happened or what the calamity even was; some speculate nuclear war, others think it was a pandemic, and at least one sect argues that [[CaughtUpInTheRapture the Rapture came and went]] and the remaining humans the leftover rejected sinners. If Dynamix's canon is to be believed, aliens were involved somehow. This apocalyptic event is simply known The Devastation. Humanity undergoes a ''very'' specified RobotWar as their second apocalypse, known as The Fire.
* ''VideoGame/AMindForeverVoyaging'': the world in 2081 is portrayed as a post-apocalyptic ruin filled with barbaric gangs and feral dogs. It's never explained just how civilization collapsed; the player character has no memory of the event and the surviving humans aren't exactly keen to enlighten you. Given the multiple environmental and political crises plaguing the world in 2071, it's highly likely that there was more than one cause.

* ''VideoGame/DragonAgeOrigins'' isn't quite AfterTheEnd, but the origin of the [[OurOrcsAreDifferent Darkspawn]] who pour out in hordes to kill everyone from time to time are not truly known. The dominant religion claims they were created when a group of powerful mages broke into the Creator's city and were cursed for doing so, but the game makes it clear that no-one really knows and suggests this may just be a fable warning about the hubris of humanity.
** ''VideoGame/DragonAgeInquisition'''s main antagonist claims to be one of those mages which may support the legend being true, but it's still never shown that he's actually telling the truth, and the apparent involvement of gods from other pantheons suggests that at the least there's more to the story than that.
* A recurring apocalypse of unknown cause is central to the background of ''VideoGame/MassEffect''. Discovering the truth and then actually convincing other people of it forms a large part of the first two games.
* In ''VideoGame/{{Obduction}}'', there's a theory among some of the characters that the alien seedpods that randomly abduct people to a strange planet are doing so in order to preserve the human species against some unknown but imminent cataclysm. [[spoiler: They are correct, as seen in the bad ending (and one specific vantage point in a late-game area): we don't know what went wrong, but it's apparent that Earth got messed up, as there are scorch marks, ruins, and massive dust clouds roaming the surface.]]

* ''VideoGame/FateExtra'': The world of ''Fate/Extra'' is quite different from the real world or the world as it exists in most other ''Franchise/{{Nasuverse}}'' stories: something happened in the 1970's that lead to a great disaster and resulted in all magical energy in the world vanishing, never to come back. What form this disaster took, and what the immediate consequences of it were, are all unknown. All that is known is that it was a global catastrophe that altered the course of human civilization. WordOfGod states that the root cause was a group of vampires attempting to perform the Aylesbury Ritual to awaken the Dark Six (a kind of vampiric messiah figure) and [[GoneHorriblyWrong failing terribly at it]], but beyond that any details are unknown.

* ''VideoGame/HyperLightDrifter'': The world is littered with the ruins of a past civilization that was destroyed after the arrival of the Titans who’s corpses are scattered throughout the land. Just what exactly happened is unknown and none of the characters show any particular interest in finding out; as far as they know or care, the world’s always been like it is. Some hints are dropped that [[spoiler:the species your character belongs to may have been responsible, or at least played a part in it.]]
* ''VideoGame/{{Beware}}'': The world you traverse is a desolate, muddy ruin filled with car wrecks and cow skeletons, and the only other living beings you encounter there are either people who don't trust you enough to speak to you or ''things'' out to kill you. It's possible to reactivate an old projector showing an endless traffic jam and news slogans referring to a famine and blackout that apparently overwhelmend the government and led to the infrastructure collapsing. However, what caused them, how far they extend and how they're connected to the aforementioned {{Humanoid Abomination}}s now stalking the land is unknown.
* The only thing known about the apocalypse in ''VideoGame/NuclearThrone'' is that it was caused by nukes, heavily irradiating the world and its inhabitants, [[AfterTheEnd creating a barren wasteland in its wake]].
* ''VideoGame/WorldOfWarcraft'': The Apexis civilization which once dominated Draenor was wiped out in some unknown cataclysm. ''Chronicles'' did eventually reveal a civil war ended with the detonation of a FantasticNuke which nearly wiped out the arakkoa and destroyed all records of what happened.
* The nature of the apocalypse in ''VideoGame/{{Fallout}}'' is obvious and widely-known; a global thermonuclear war. But nobody seems to know ''how'' that fateful nuclear exchange started, nor who fired the first shot that kicked it all off. The world was already in a pretty tense state, with the US having just come out on top in a brutal war with China and most of Europe collapsing into quarreling nation-states, so there are plenty of suspects, but no one particularly cares about finding out who shot first; few are concerned with such historical information when they are fighting for survival everyday.
* ''VideoGame/{{Lisa}}'': There was an apocalypse event called "The Great White Flash" that eliminated all women. And that's all we know. We don't know what it was, what caused it, what it actually ''did'' to the women, or if the AfterTheEnd setting was directly due to the Flash or if society simply collapsed due to half the population vanishing.
* ''VideoGame/{{Nier}}'': The game is suggested to take place in the far future, but what exactly wrecked mankind's civilization isn't well-explained. There's talk of [[VideoGame/{{Drakengard}} a great "Dragon" and "Giant" suddenly appearing in a city]], fighting each other, and then getting killed shortly afterward, and then something called "White Chlorination Syndrome" spreading across the planet, but the details are left vague... at least, in the game itself. [[AllThereInTheManual Supplementary materials]] contain extensive timelines and details about what exactly happened and how it lead to the state of the world in ''Nier''.
* ''VideoGame/{{Destiny}}'' takes place in the aftermath of the Collapse that ended human civilization, leaving ruins strewn across the solar system and the survivors gathered into the Last City on Earth. For the longest time, what actually happened in the Collapse was a mystery, as was the exact nature of the [[UnseenEvil Darkness]] said to have caused it. Details about both were slowly revealed across the game's lifespan and [[VideoGame/Destiny2 its sequel's]]; ultimately, a [[AllThereInTheManual lore book]] in ''Destiny 2'' mentioned without much fanfare that it mostly involved the Darkness barraging every world with natural disasters, too many to respond to or recover from.
* The nature of the apocalypse in ''VideoGame/IAmAlive'' is left vague, only that most of the world is now covered in toxic dust and human civilization has collapsed.
* Exactly ''what'' happened to Earth in ''VideoGame/{{Outriders}}'' isn't elaborated on. It's treated as a analogy for global warming caused by human excess, but it's also mentioned the planet was ultimately destroyed by earthquakes which all the pollution and energy-guzzling appliances in the world isn't going to cause.

* In [[VisualNovel/DanganronpaTriggerHappyHavoc the first game]] of the ''Franchise/{{Danganronpa}}'' series, the last trial, the Mastermind [[spoiler:(a.k.a. Junko Enoshima)]] reveals that the reason the students weren't actually trapped, but instead choose to stay inside the school for the rest of their lives was because of "The Worst, Most Despair-inducing Event in the History of Mankind" that caused the downfall of society. However, the specifics of the Tragedy aren't shown until [[VisualNovel/Danganronpa2GoodbyeDespair the second game]].

* ''WesternAnimation/AdventureTime'': The Great Mushroom War is the reason behind the formation of the Land of Ooo, but for the longest time, the fact that the world was even AfterTheEnd was just hinted at. Even by the end of the show, the details -- who was fighting whom, the exact nature of the weapons used, how or whether it's connected to [[TheMagicComesBack the rise of magic]], etc.-- [[RiddleForTheAges are never entirely revealed]], though enough hints are dropped for you to piece together a vague idea of what happened.
* ''WesternAnimation/AmericanDad'': The episode "The 200" begins with a grizzled and tattooed Stan returning to a ruined Langley Falls in search of his missing family, and the only thing we find out is that something called "The Wave" destroyed the world and wiped out most of humanity, with the few survivors being driven to cannibalism to survive. [[spoiler: It's not until the last few minutes that it's revealed that the global apocalypse was caused by Roger accidentally being trapped inside a particle accelerator, which combined with his BizarreAlienBiology to create a WorldWreckingWave that swept across the planet, reducing it to ashes. It also led to an army of Roger copies, each one being one of his personas, popping into existance.]]

* In [[Literature/ThePrecipice ThePrecipice]], a hail of meteors created a number of large craters fifty years before the story proper; it is speculated that this was the source of Superpowers, and it is mentioned that millions died, but in the decades since the world has settled into a kind of normalicy.

* ''LightNovel/HumanityHasDeclined'': The human race is slowly dying out; exactly why is never spelled out, and the humans seem no worse than melancholy about the notion.

* The world of ''Film/MadMax1'' takes place in an anarchic society, where law and order is next to non-existent and ultra-violent gangs have risen up to rampage against decent people. [[AllThereInTheManual Production documents state that the first movie takes place after a war between Saudi Arabia and Iran, which led to an oil shortage]]. But what happened between the first movie and ''Film/MadMax2TheRoadWarrior''? Things got ''worse''. It is never really explained how the world got to this horrific state, but in [[VideoGame/MadMax the video game]], Max basically says that - as far as he can tell - literally everything that could go wrong ''did'' go wrong, all at once, and consequently nobody really knows which specific catastrophe [[TheLastStraw actually caused the apocalypse]]; the collapse of society, massive wars destroying countries, oceans drying up, super-plagues everywhere, and more.

[[folder:{{Anime}} & {{Manga}}]]
* ''LightNovel/HumanityHasDeclined'': The human race is slowly dying out; exactly why is never spelled out, and the humans seem no worse than melancholy about the notion.

* ''LightNovel/SundayWithoutGod'': The legends say that God abandoned the world fifteen years prior, and as a result no one can truly die or give birth. Other characters doubt this story, believing instead that one day, ''everyone'' became a RealityWarper and collectively wished to live forever, thus distorting the nature of death. Whatever the reason for why the world is slowly coming to a standstill, the characters have to deal with the lack of true death and [[BeCarefulWhatYouWishFor the consequences of people's deepest wishes coming true]].

* The reason for the [[TheMagicGoesAway vanishing of the heroes]] in ''ComicBook/Marvel2099''. Sometimes it's vaguely alluded that the heroes tried their best to save everyone, [[TheBadGuyWins but failed]]. But never more than that, because by 2099, the age of heroes has faded into myth. The 2019 soft reboot is the first incarnation of the 2099 books to ever explicitly show what caused the world to become a dystopia: [[spoiler: It's [[ComicBook/DoctorDoom Doom]]'s fault]].

* ''ComicBook/TheWalkingDead''. A smaller example. We know that the dead walking again caused the end, but why it started happening is never really discussed. WordOfGod has even said that [[RiddleForTheAges he has no plans to explore the reasons either]].

* ''ComicBook/XenozoicTales'': In 2020, the Earth went batshit crazy with natural disasters and humanity was forced to hide away in great underground shelters. They re-emerge 450 years later, once everything has calmed down, to find a sort of OneMillionBC world where prehistoric creatures of all eras roam through ancient cities that have been ReclaimedByNature. How any of this happened is never revealed; speculation is made and hints are dropped (particularly regarding mysterious meteors containing ''[[AppliedPhlebotinum something]]'' that [[MutagenicGoo causes havoc on evolution]]), but solid answers are few and far in between, and arguably just deepen the questions.

* ''VideoGame/{{Beware}}'': The world you traverse is a desolate, muddy ruin filled with car wrecks and cow skeletons, and the only other living beings you encounter there are either people who don't trust you enough to speak to you or UncannyValley-straddling ''things'' out to kill you. It's possible to reactivate an old projector showing an endless traffic jam and news slogans referring to a famine and blackout that apparently overwhelmend the government and led to the infrastructure collapsing. However, what caused them, how far they extend and how they're connected to the aforementioned {{Humanoid Abomination}}s now stalking the land is unknown.

* The game ''TabletopGame/BaseRaiders'' takes place in a superhero universe Earth where an event simply known as "Ragnarok" made all of the superheroes and supervillains of the planet simply disappear overnight. It must have been something of ''[[CrisisCrossover insane]]'' proportions for this to happen, but if there is anybody on the planet who knows the specifics, they ain't telling. The only thing the player characters care about if that this has left a myriad of secret bases full of comic-book superscience and magic gear lying around ready to be plundered and sold on the black market, justifying the game's angle of "modern-day DungeonCrawling".

* ''WesternAnimation/LoveDeathAndRobots'': In "[[Recap/LoveDeathAndRobotsThreeRobots Three Robots]]", there are conflicting reports as to why humanity went extinct. A nuclear holocaust is proposed first, and 11-45-G's research suggests it was environmental catastrophe brought about by environmental degradation and climate change. The cats claim ''they'' did it because humanity [[YouHaveOutlivedYourUsefulness had ceased to be of any use to them once they were given thumbs]], but [[UnreliableExpositor this isn't reliable]] when the same cats are pretending they can explode if they aren't petted on demand.

* ''WesternAnimation/LoveDeathAndRobots'': In "[[Recap/LoveDeathAndRobotsThreeRobots Three Robots]]", there are conflicting reports as to why humanity went extinct. A nuclear holocaust is proposed first, and 11-45-G's research suggests it was environmental catastrophe brought about by environmental degradation and climate change. The cats claim ''they'' did it because humanity [[YouHaveOutlivedYourUsefulness had ceased to be of any use to them once they were given thumbs]].

* Whatever destroys the Earth in ''VideoGame/Seedship'' is never explained.

* ''Franchise/PlanetOfTheApes'': The details involving the nuclear war in the 1970s series are never explored. All that matters is that the apes inherited the world.