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[[quoteright:325:[[Franchise/StarWars https://static.tvtropes.org/pmwiki/pub/images/e1d1c5a59680acb66653b940ce522618.png]]]]

->''"Welcome to the underworld. My world. Here, there are worlds above worlds above worlds, going farther up than you can imagine. The trash of each one flows down to the one below until it all ends up here."''
-->-- '''Grewishka''', ''Film/AlitaBattleAngel''

This part of the city used to be part of a sprawling metropolis, or maybe it was a whole city of its own, but something happened. Maybe an earthquake or another disaster buried it, or maybe they just decided to [[LayeredMetropolis build a new city on top of it]] and, in time, forgot the old one. Maybe the burying was gradual, as people built higher and higher and gradually abandoned the older, lower parts of the city. Whatever the cause, what we have now is this trope: an older, often abandoned city that exists underground and directly underneath a megacity. Sometimes this becomes a cycle, with successive layers of older cities as you go deeper.

This isn't just any [[BeneathTheEarth underground area]]; the Under City used to be above the earth before being buried by whatever occurrence. Could be a whole GhostCity, or a part of an AbsurdlySpaciousSewer. If it remains inhabited, it will likely end up as an UndergroundCity and makes the WretchedHive above it look like a paradise.

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!!Examples

[[foldercontrol]]

[[folder:Anime and Manga]]
* ''Manga/{{Berserk}}'''s Tower of Rebirth is a massive prison tower built on the ruins of an older city.
* In the first anime of ''Anime/FullmetalAlchemist2003'', there is a hidden city [[spoiler:under Central that has been destroyed in order to create a Philosopher's Stone.]]
* The city in Osamu Tezuka's ''Anime/Metropolis2001'' has a lower level where all the low-income humans live and an even lower level inhabited only by worker robots maintaining the machinery that powers the city.
[[/folder]]

[[folder:Card Games]]
* ''TabletopGame/MagicTheGathering'': The plane of Ravnica is a fantasy-themed CityPlanet that has been such for many thousands of years. As a result, space is very much at a premium, and its natives are usually forced to build ''up''. The result is that, over time, streets, buildings and entire neighborhoods are abandoned as the become buried beneath a steadily increasing mass of masonry, resulting in a multilevel undercity which, besides serving as Ravnica's sewers and rubbish tip, is home to the Golgari necromancers and rot farmers (the city's main food providers, who turn all that sewage back into edible plant matter), Dimir spy bases, roving BigCreepyCrawlies and -- for those who can actually make it down there -- troves of archeological treasure. Some of the deepest levels of the Undercity are so old that they date to before Ravnica the city swallowed Ravnica the world, created from ancient settlements and tombs buried beneath the world-city's growth.
[[/folder]]

[[folder:Comic Books]]
* ''ComicBook/{{Aquaman}}'': In ''ComicBook/Aquaman2011'', the seven hidden kingdoms of Atlantis thrived under King Atlan's rule, but following the coup d'etat and subsequent sinking of the continent, they've been forgotten to history.
** The Trench: a ravenous cavern dwelling race of subhuman water breathers who adapted to living in the sea floor.
** Xebel: Secessionist clan of criminals exiled from Atlantis to a cosmic Alcatraz within the Bermuda Triangle, occupied by water bending merefolk.
** Ninth Tride: The slums on the ocean floor, home to the dregs of Atlantean society.
* ''ComicBook/BatmanBeyond'': In ''ComicBook/{{Batman Beyond|Rebirth}}: Neo-Gothic'': The first issue reveals that underneath Neo Gotham lies "Lower Gotham" or "The Gotham Deep", the decaying remains of the original Gotham City that Neo Gotham was built on top of after Bruce Wayne lost control of his company. The only residents shown to remain in this portion of Gotham are poor folk, mutants, gangs, and Killer Croc.
* ''ComicBook/{{Diabolik}}'': Clerville has vast catacombs, parts of which seem to have been on the surface in the past. It's inhabited by many homeless people, parts of whom have organized themselves in the People of the Shadows, and Diabolik frequently uses it for his heists and was taught how to get around by the People of the Shadows during a brief alliance.
* ''ComicBook/DisneyDucksComicUniverse'': Underground Duckburg in Creator/DonRosa's version of the city. The Beagle Boys in particular like to use it as a hideout.
* ''ComicBook/JudgeDredd'': New York has become this in the comic's time. MegaCity One is built on top of it and several other East Coast cities. It's a very nasty place that no sane person would want to venture into, being filled with mutant tribes, monsters (including werewolves), and even ''[[Franchise/{{Alien}} Xenomorphs]]''.
* ''ComicBook/SpiderMan'': ''ComicBook/FriendlyNeighborhoodSpiderMan'' Vol 2 introduces "Under York", a subterranean duplicate of New York City populated by [[AmazingTechnicolorPopulation orange-skinned humans]] with a vague steampunk aesthetic. Apparently it has a long-standing truce with New York's government, which is threatened when Spider-Man ends up in the middle of a dispute with the ruling family.
* ''ComicBook/{{Venom}}'': In ''ComicBook/VenomLethalProtector'', Venom spent the first story arc in the "Underground City", a section of San Francisco that was buried and contained 1800s-era architecture (the city had simply built over it for some reason). Sadly, this was all mostly forgotten by the next miniseries.
[[/folder]]

[[folder:Film]]
* ''Film/AlitaBattleAngel'': There's a huge desolated wasteland underneath Iron City, which Grewishka says he used to call home and battles Alita there.
* Ralph stumbles across the lower, abandoned areas of the Internet in ''WesternAnimation/RalphBreaksTheInternet'', where long-forgotten websites like Platform/GeoCities are located. The only inhabitants left are black market dealers and malware programmers.
* ''Franchise/StarWars'' has [[CityPlanet Coruscant]], where the ground is always buried under at least five layers -- often more -- of ancient skyscrapers. The [[CityPlanet global city]] has been growing upwards for millennia, steadily burying its older layers and districts under each new accretion of urban growth. This also results in the mother of all {{Layered Metropolis}}es, with districts growing increasingly unsafe and sparsely settled as one heads further down until the ruins of Coruscant's earliest cities are reached at the almost mythical ground level. ''Legends'' texts like ''Literature/TheIllustratedStarWarsUniverse'' indicate that the Empire used the lowest levels to hide [[TortureCellar interrogation facilities]], while the sub-basements of such areas were claimed by clans of troglodytes descended from criminals who fled to the undercity to escape arrest.
[[/folder]]

[[folder:Literature]]
* In ''[[Literature/TheRiftwarCycle A Darkness at Sethanon]]'', the titular Sethanon was built right on top of an ancient [[{{Precursors}} Valheru]] city.
* ''Literature/{{Discworld}}'':
** Because [[CityOfAdventure Ankh-Morpork]] is built on soft loam, near an extremely turgid river, the ground levels of its buildings find themselves buried every generation or so. The standard remedy is to just build another level on top and cut open new doors, so now the city descends through the earth to an unknown depth. This has caused friction between the [[OurDwarvesAreAllTheSame dwarfs]], who traditionally view anything underground as theirs, and the city's government, who think of those areas as sub-sub-basements and would rather not have unknown factors tunneling through them.
** Also from ''Discworld'', the mine-city of the Low King of the Dwarfs is built mostly under the surface town of Bonk.
* In the ''Literature/DoctorWhoNewAdventures'', there's the Undercity of [[MegaCity Spaceport Overcity Five]] -- or, as we would say, London. In this case, London wasn't buried: the entire Overcity floats above it on AntiGravity engines.
* The Undertown in ''Literature/TheDresdenFiles'' is located under Chicago, consisting of old buildings that sank into the ground under their own weight. It is populated by various supernatural nasties.
* Almost every moving city in ''Literature/MortalEngines'' is built in multiple layers like a pyramid, the further a city is up the food chain, the more layers it has. The topmost layer is usually pleasure gardens for the ruling elite, while the bottommost layer is the hot and polluted engine room that uses slave labour to keep the wheels of the city moving. An interesting inversion is Arkangel, whose "best" layer is actually the one in the exact middle due to the extreme cold of the Arctic where the city roams.
* Creator/NeilGaiman's ''Literature/{{Neverwhere}}'' has a London Below which consists largely of places buried and forgotten by London Above.
* In "Literature/Nightfall1941", archaeologists discover that a hill near their city is actually the ruins of several older cities, piled on top of each other. They all burned down at suspiciously regular intervals. [[spoiler:It coincides with nightfall on a planet of (near-total) daytime. People panic and start burning things to bring back the light and wind up destroying everything. Over and over and over...]]
* At the start of ''Shiva 3000'', the protagonists escape the Juggernaut laying waste to the city above by escaping into this area.
* Inverted in Creator/CSLewis's ''Literature/TheSilverChair''. The thriving kingdom of the Lady of the Green Kirtle is underneath the ruined city of the giants. [[spoiler:And there's an ''even deeper'' land beneath her kingdom]], which is abandoned but not for long.
* In ''Literature/{{Tunnels}}'', the Colony is located in a gigantic series of caverns beneath London, while the abandoned Eternal City is between them. Beneath the Colony lies the Deeps, and beneath that is the Pore [[spoiler:and the other Pits]], and beneath ''those'' lies [[spoiler: the Garden Of The Second Sun]].
[[/folder]]

[[folder:Live-Action TV]]
* ''Cities of the Underworld'' is a documentary series that aired on the History Channel and explored subterranean structures under various cities and historic sites around the world. See the Real Life section below.
* Former St. Louis in ''{{Series/Defiance}}'' which was largely buried when alien terraforming machines [[HostileTerraforming went wild]]. Bits of it, including the famous Arch, remain on the surface.
* Modern day [[WhereTheHellIsSpringfield Granville]] in ''Series/GhostWhisperer'' is built on top of Old Granville...[[DarkAndTroubledPast with good reason]].
[[/folder]]

[[folder:Tabletop Games]]
* The ''Dark Dungeon'' RPG supplement ''Samaris, Island of Adventure''. At one time the entire island of Samaris was covered by a giant city, which was also called Samaris. The city was destroyed in a war between the North (led by the demonic wizard king Acecerax) and the South (led by the demon witch empress Vekna) two hundred years ago. Southport (the largest city on the island), Northport, Eastport, Westport, and Zentrumstadt are smaller cities built upon its ruins.
* ''TabletopGame/DungeonsAndDragons'': In the backstory of the Judges' Guild module ''Dark Tower'', a small village grew up around the White Tower of Mitra. When the Black Tower of Set appeared nearby, the village was buried by the landslides caused by the battle between the two towers. Within a decade a new village of treasure seekers called Mitras's Fist was established on the ground where the old village had stood. When the new villagers began digging down to find the old village, imagine their surprise when they found someone digging ''up'' to meet them...
* ''TabletopGame/ForgottenRealms'' has cities built this way, particularly big and old ones like Westgate. In another way, Waterdeep stands on the still active Undermountain complex and [[NotSoSafeHarbor Skullport]] city and Ravens Bluff stands above an abandoned dwarven city under which there's in turn an abandoned drow city.
* ''TabletopGame/MutantsAndMasterminds'': Emerald City has the Undercity, created a hundred years ago when the city just built over flooded buildings, and rediscovered in the sixties by a hippie who now offers tours of the safer areas. Since then, other parts of it have become occupied by the homeless, low-level metacriminals trying to lie low, the occasional cryptid, and there's even connections to [[BeneathTheEarth Sub Terra]].
* ''TabletopGames/RocketAge'''s Martian cities have extensive networks of service tunnels and sewers underneath the streets, often linking the entire city together.
* ''Tabletopgame/Warhammer40000'': Imperial Hive Cities, each of which is usually a [[MegaCity megalopolis]] and sometimes an {{arcology}}, will almost invariably have such an "underhive" as the hive is continuously built upwards and older buildings and streets are built upon and buried. The formation of an underhive is considered the natural consequence of the history of ''most'' established cities in the Imperium of Man. As civilization stays as close to the top as it can manage, the underhive has a population density so thin that it can be considered derelict, except for the mutants, gangs, cults, fugitive psykers, and any other criminal element that seeks to stay away from prying eyes. Also notable is that the areas underneath range from claustrophobic maintenance tunnels to deserted city districts to enormous, abandoned underground industrial sites.
[[/folder]]

[[folder:Toys]]
* ''Toys/{{Bionicle}}'':
** Metru Nui under the island of Mata Nui.
** Except only one of them is a city, and it's more like Mata Nui is on top of Metru Nui [[spoiler:and the rest of the Matoran Universe]].
[[/folder]]

[[folder:Video Games]]
* The Undercity in ''VideoGame/BaldursGate'' is an ancient settlement located in a cave underneath the eponymous city. It is apparently big enough to house an enormous temple of Bhaal and many supporting structures.
** And of course the Underdark in the sequel houses three large dwellings, one of Mind Flayers, one of Beholders, and a gigantic city of Drow.
* Wonder City in ''VideoGame/BatmanArkhamCity''.
* ''Franchise/TheElderScrolls''
** ''[[VideoGame/TheElderScrollsIIIMorrowind Morrowind]]'': Mournhold in the ''Tribunal'' expansion was built over the ruins of Old Mournhold which was destroyed by Mehrunes Dagon thousands of years prior. Naturally, you'll be spending quite a bit of time there. And that's not the ''only'' city Mournhold was built over, [[spoiler: though the [[OurDwarvesAreDifferent Dwemer]] city of Bamz-Amschend was intentionally built underground in the first place]].
** In ''[[VideoGame/TheElderScrollsIVOblivion Oblivion]]'', Part of the Imperial City's {{Absurdly Spacious Sewer}}s are old Ayleid constructs whose purpose have been lost over the millennia. Whether they ever actually were above-ground is left ambiguous, however.
* In ''VideoGame/{{Fallen London}}'', bats stole Victorian London, the game's setting, from the surface and brought it underground. And it's far from the first city to have suffered this fate.
* ''VideoGame/FinalFantasyVII'': Midgar's 8 sectors are each comprised of the areas above and below the plates, with the upper city being for the affluent and the lower city being for the poor.
* ''VideoGame/FirstEncounterAssaultRecon'''s Vivendi expansion ''Perseus Mandate'' features the Old Underground Metro Area, a buried section of a commercial district dating back to the '50s or '60s, beneath the modern city of Fairport, where [[PlayerCharacter The Sergeant]] and Lt. Chen take refuge while running from the Origin Facility explosion. According to Chen, the place was buried in an earthquake and Fairport was built on top of it. He also states that the area remained open to tours, presumably historical ones, and several points of it have functional electric lighting. [[BigBoosHaunt It's the only location in the expansion where you are attacked exclusively by paranormal enemies, and Alma is not shy about making appearances]].
* The Undercity in ''[[VideoGame/GuildWars Guild Wars: Factions]]'' started out at ground level, but by the time of the game's present day is effectively underground due to so much being built atop it. Kaineng City as a whole was explicitly inspired by the [[https://www.cnn.com/travel/article/kowloon-walled-city/index.html Kowloon Walled City]].
* ''VideoGame/KingdomHeartsIII'' reveals that Daybreak Town, the main setting of ''VideoGame/KingdomHeartsX'', experienced a calamity sometime ago, and now exists as underwater ruins beneath Scala ad Caelum.
* ''VideoGame/KnightsOfTheOldRepublic'': Taris has four levels -- the decaying (but still pretty decent) Upper City where the wealthy live, the Middle City (where the working and middle class live), the Lower City (a slum controlled by gangs and the local crime boss), and the Undercity -- a wasteland crawling with [[PlagueZombie rakghouls]] and a small settlement comprised of exiled criminals, political prisoners, and their descendants. While there is a HopeSpot brought about if the player completes a quest with the light-sided option, the [[VideoGame/StarWarsTheOldRepublic sequel]] reveals that [[ShootTheShaggyDog those who survived the initial bombardment survived a couple of generations before succumbing to disease, toxic waste, and rakghoul attacks.]]
* ''VideoGame/PaperMarioTheThousandYearDoor'' has the ancient city buried under Rogueport.
* ''VideoGame/SaintsRow2'' has Old Stilwater, an earthquake-ruined underground district from approximately 1940-1965, inhabited by hobos, accessed by entering the old mission house.
* [[spoiler:Tokyo]] in ''VideoGame/ShinMegamiTenseiIV'' was sealed underneath a gigantic rock ceiling before the start of the game -- how long depends on [[YearOutsideHourInside which side of the ceiling]] you're on: 25 years on the inside, and around 1500 on the outside.
* The Lost City (Karath Din) in the ''VideoGame/{{Thief}}'' game series.
* In ''VideoGame/{{Torchlight}}'', you explore a stack of these, many layers deep.
* ''VideoGame/VagrantStory'' has an Undercity area, notable for its high-density population of undead.
* New City in ''[[VideoGame/{{Wizardry}} Wizardry VII: Crusaders of the Dark Savant]]'' was built on top of the long-abandoned Old City.
* ''VideoGame/WorldOfWarcraft''
** Old Ironforge is located under the dwarven capital of Ironforge.
** Also in ''VideoGame/WorldOfWarcraft'', a literal inversion: the Undercity is the capital of the undead race the Forsaken, while the old city of Lorderon above it is the mostly-abandoned ruins.
[[/folder]]

[[folder:Webcomics]]
* ''Webcomic/BattleBunnies'' has the neutral trade hub named Azkendaren built atop the ruins of an earlier civilization. The old city has become a ForbiddenZone, where overuse of magic charms resulted in giant armored monsters prowling the ruins, among other hazards.
[[/folder]]

[[folder:Western Animation]]
* ''WesternAnimation/{{Arcane}}'': The Undercity of Piltover (which will one day become the city of Zaun) is a classic inhabited example. It's horribly polluted with fissures poisoning the air and [[WretchedHive rife with crime and poverty]].
* In ''WesternAnimation/AvatarTheLastAirbender'', Old Ba Sing Se is buried under Ba Sing Se.
* Old New York in ''WesternAnimation/{{Futurama}}'' is the original New York City that was apparently leveled by an AlienInvasion, later revealed to actually be [[spoiler:the Swedish Air Force battling Bender and his fleet of spaceships after he stole the Nobel Peace Prize]]. Eventually, the city of New New York was simply built on top of the ruins, which had the sewers rerouted through them. In the 31st century, the remnants of Old New York are still standing, derelict, beneath New New York, home only to the sewer mutants.
* ''WesternAnimation/{{Motorcity}}'': The futuristic city of Detroit Deluxe was constructed by encasing all of old Detroit beneath a gigantic metal shell and using that as its foundation. Old Detroit, or Motorcity, is now a rundown but lively urban jungle where the sun never shines, populated mainly by street gangs with cool cars.
* ''WesternAnimation/TeenageMutantNinjaTurtles2003'' has a lost alien city below New York, as well as a rotting system of abandoned mining tunnels where some of The Shredder's mutates lived.
[[/folder]]

[[folder:Real Life]]
* Moscow has a lot of Soviet-era underground works, partly civilian (Metro) but mostly of Cold War-era Soviet military origin. Urban legends tell about a whole system of special Metro for the government and underground vault-cities in case of a nuclear war, for generals and officers.[[note]]Given the Soviet Union's general resource allocation and priorities, particularly under Stalin and Brezhnev, not to mention declassified equivalent US projects, this probably has at least some basis in actual fact. Perhaps not underground cities, but it wouldn't be unexpected to find more than a few subterranean office parks and military operations centers[[/note]] Also included are older Tsarist era ruins and basements.
* Underground Seattle. This was a part of the late 19th century Seattle business district that was buried when the streets were regraded to between 12ft and 30 ft (3.6m to 9.1m) above their former height after the Great Seattle Fire of 1889. The areas formerly constituting sidewalks and alleys were left unfilled or were later excavated, and connecting tunnels were created under the roads- some intentionally to create maintenance tunnels and pedestrian bypasses for busy streets, and others during the TheEdwardianEra and TheRoaringTwenties to ease the transport of contraband and allow the former street level to serve as a literally underground combination RedLightDistrict and [[TheCityNarrows City Narrows]]. This created an eerie network of tunnels lined by 19th-century storefronts, many now serving as basements to the buildings above, though a few remain in use as bars or other establishments seeking to play off of the history.
* Mexico City is built on top of the ancient Aztec capital of Tenochtitlan.
* Western Guatemala City is built on top of the old Mayan city of Kaminaljuyú.
* Many old European cities like Rome or Paris have catacombs beneath them.
** Rome is a city of four million people, but only has two subway lines. This is because it's impossible to dig anywhere in Rome without hitting ''some'' set of ruins.
** Ancient Rome often used the practice of burying larger buildings and building on top of them rather than demolishing them. The Palatine hill is covered with ruin on top of ruin and has an impressive network of caves and tunnels under all of it.
* [[https://en.wikipedia.org/wiki/Tell_(archaeology) Tells]] are distinctive-looking mounds mostly found in the Middle East, formed when cities are built in the same spot [[RecursivePrecursors over and over and over again]]. Digging into one can reveal the buried remains of more than one incarnation of the city, each sitting on top of its predecessors.
* Çatalhöyük was an ancient city with eighteen levels of settlement, thanks to old houses being partially demolished and new houses being built on the rubble.
[[/folder]]
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