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[[quoteright:300:[[ComicBook/JudgeDredd http://static.tvtropes.org/pmwiki/pub/images/megacityone300pxwidth.png]]]]

->''"I was born in apartment block Seven of Nine, in the Tertiary Adjunct of Unimatrix Zero One," replied Annika in a clipped tone. "An arcology so large it contained the entire population of Greater Germany — the builders had to fill in the North Sea just to provide parking space."''
-->-- '''Plan 7 of 9 from Outer Space'''

A city whose population is larger than a reasonably sized country. The actual size can depend on the average city size of the setting, but for modern or sci-fi settings, you can assume that the number of citizens goes into the hundreds of millions or even billions.

Depending on the setting you can expect to see a lot of tall buildings, endless suburbs and futuristic ways to get around. If you are lucky the author may have even thought of the troubles with providing food and water for all the inhabitants as well as the problems for the environment so many people naturally generate. If you are unlucky however, the heroes may find themselves alone at times and places where that should be impossible given the population density.

Notice that, despite the introduction, a given city does not count as a Mega City just because it is bigger than ''some'' country. For example, in real life a whopping 41 countries around the world have less than a million inhabitants, 17 of those have less than 100,000, and cities of that size in other countries are normal and therefore would not be seen as mega cities.

The Mega City will probably be the capital or HubCity, and if it's not a MerchantCity, there'll definitely be a BazaarOfTheBizarre if you know where to look. If its land area is restricted, expect it to be a SkyscraperCity.

Occasionally, a Mega City will grow so large that it will become a CityPlanet.



[[folder:Comic Books]]
* The City in ''ComicBook/{{Transmetropolitan}}''. It's unclear where it is or just how big it is, but some stories imply it to stretch from New York to the Great Lakes, and it's massive enough to be a deciding factor in elections.
* The world of ''ComicBook/JudgeDredd'' is divided into these kind of cities. Much of the world outside the Mega Cities was destroyed in the Atomic War of 2070, leaving the metropoles as the last centers of advanced civilization due to their missile shields having withstood the worst nuclear attacks. Dredd's home city of Mega City One grew from [=BosWash=] until it covered the entire eastern seaboard. In fact, the whole point of the Apocalypse War arc was to trim its sheer size down, as it had become too big.
* Downlode in ''ComicBook/SinisterDexter'' stretches from northern Spain to west Poland.
* ''ComicBook/TheMightyThor'' #372, part of a storyline involving TimeTravel, says that in the future the entire east coast of the USA will be covered by the [=megacity=] of Brooklynopolis (which will be policed by the [[AlternateCompanyEquivalent oddly-familiar]] [[ComicBook/JudgeDredd Justice Peace]]).
* The city of [=NorthAm=] in ''ComicBook/MagnusRobotFighter,'' which covers all of North America.

[[folder:Fan Fiction]]
* The city of Los Angeles, California has become one of these in the aftermath of [[TheEndOfTheWorldAsWeKnowIt the Vanishing]] on ''Fanfic/CoreLine''. The ''[[https://en.wikipedia.org/wiki/Parker_Center police headquarters alone]]'' has become a multi-mile-high heavily-armored arcology. The old Los Angeles became an underground city wherein all kind of CyberPunk tropes are done willy-nilly, and it's essentially become the town's Red Light District.

[[folder:Films -- Live-Action]]
* The pre-war human cities in ''Film/TheMatrix'', which "spanned hundreds of miles" and needed armies of robots to maintain themselves. It's implied that the entirety of civilization within the Matrix is one of these, dubbed "the city" for lack of need for a more specific name.
* The BigApplesauce has become this in the 1930's films ''Film/{{Metropolis}}'' and ''Film/JustImagine'' -- in those days New York was pretty much the only skyscraper city in existence.
* ''Film/{{Avatar}}'': In the extended version, and in [[AllThereInTheManual supplementary materials]] the cities of Earth have become this.
* ''Franchise/StarWars'' has the city planet of Coruscant. It's rumored that one can walk all the way around the planet without ever setting foot on its surface.

* In Creator/IsaacAsimov's ''Literature/TheCavesOfSteel'', all of Earth's population lives in eight hundred arcologies known as "Cities". The average population of each City is eleven point two million. The governments of three large cities (New York, Philadelphia and Washington) are considering merging into one single ''Mega'' Mega City, but the logistics of maintaining and governing such a large conglomerate have so far prevented any action on the plan.
* Later in the ''Robots/Empire/Foundation'' series, Trantor, and presumably a few other worlds, are globe-spanning versions of these with populations in the billions. Trantor is very much the model for Coruscant.
* Literature/{{Discworld}}: While Ankh-Morpork only has a million inhabitants, it is still the biggest city in the [[MedievalStasis setting]]. In ''Discworld/TheFifthElephant'', Carrot points out that it's actually the largest dwarf city, having more dwarfs than any purely dwarf city. (This isn't as far-fetched as it may seem -- a RealLife example is the city of São Paulo, whose Italian community is larger than any city in ''Italy itself''.)
* In the ''Literature/MythAdventures'' series the dimension of Deeva is entirely taken up by an open-air market.
* ''Literature/TheThirteenAndAHalfLivesOfCaptainBluebear'': The Capital of the continent of Zamonia, Atlantis, has over 200 million inhabitants.
* The arcologies in ''Literature/TheNightsDawnTrilogy''.
* Creator/VladimirVasilyev's ''Literature/BigKievTechnician'' UrbanFantasy series:
** Big Kiev in this AlternateUniverse is roughly 600 miles in diameter. Big London is also mentioned, although it may be smaller. It takes 9 hours on a train to get from the Black Sea in the southern part of town to the Center (where our Kiev, Ukraine, is located). One of the old cities absorbed into Big Kiev is L'viv. Only canned goods are available in the Center due to lack of farmland or cattle so far from the edge, unless you're willing to spend a fortune on fresh meat and fruit.
** Big Moscow is mentioned to be even larger, although younger. A military conflict is mentioned to have happened in the past between Big Moscow and Big Berlin. DoesThisRemindYouOfAnything
** This can be partially explained by cities apparently growing ''on their own'', as a jungle would. This fits into the overall theme of all machines in this world being alive. Apparently, the major cities have been slowly growing for the past 300,000 years in the novel's timeline.
* Creator/WilliamGibson's ''Literature/SprawlTrilogy'' has the titular [[TitleDrop Sprawl]], more officially known as BAMA, the Boston-Atlanta Metropolitan Axis, presumably an extension of the real Bos-Wash. Also notable for being almost completely covered by geodesic domes. Judging from descriptions in ''Literature/{{Neuromancer}}'' Chiba City and the other cities around Tokyo Bay also count.
* In one of Creator/AndreiLivadny's ''Literature/TheHistoryOfTheGalaxy'' novels, Earth cities are mentioned to have become these with populations of major cities approaching 20 billion ''each''. That's nearly triple the population of the entire world today in a single city. This is the main reason why President John Winston Hammer of the [[TheEmpire Earth Alliance]] sends a fleet to force the recently-discovered [[LostColony Lost Colonies]] into submission, so as to offload the extra population. By the time of the later novels, most of the population has moved to new colonies or died in the First Galactic War (the 30-year war with the colonies, which Earth ultimately loses) with only about 100 million people left on Earth. Most urban areas, now abandoned, are covered by lush jungles, and many surviving landmarks have been moved to other areas for preservation. After the war, the colonies emerge as the industrial, economic, and scientific power in human space, forming the [[TheFederation Confederacy of Suns]] for mutual protection (Earth isn't included).
* In F. Paul Wilson's ''[=LaNague=] Federation'' series, Earth (and some colonized planets) has several Megalops with stupidly huge buildings and nightmarish overpopulation. Food-riots are not pleasant affairs.
* Nessus from ''Literature/BookOfTheNewSun'' by Creator/GeneWolfe appears to be one of these in decline (along with rest of the planet.) It takes days to travel from its center to the outskirts. Large portions of it, however, are in ruins and inhabited by cannibals.
* ''OnTheEdgeOfEureka'' has Eleutheria, a metropolis so large it covers the planet.

[[folder:Live-Action TV]]
* ''Series/{{Aftermath}}: Population Overload'': Most of the population of North America becomes concentrated around the Great Lakes after a drought-induced mass migration. A massive mega city surrounds the lakes.

* Appropriately enough, the ''Pinball/JudgeDredd'' pinball takes place in Mega-City One.

[[folder:Tabletop Games]]
* ''TabletopGame/{{Warhammer 40000}}'' has Hive Cities, mountains of metal housing millions of inhabitants and dependent on imported food and water from neighboring [[SingleBiomePlanet Farm Planets]]. They tend to settle into very stratified societies, with the administrators and wealthiest citizens living comfortably in the Spire, while gangs, mutants, and worse struggle to survive in the dark and decaying Underhive. Many of the setting's "{{City Planet}}s" aren't actually covered entirely by urbanization, but are rather dotted with hive cities separated by the resulting {{Polluted Wasteland}}s.
** Holy Terra is a proper CityPlanet, though individual complexes stand out as pseudo Mega Cities in their own right: the Imperial Palace covers a good portion of the northern hemisphere, the Inquisition's headquarters is beneath what used to be the southern ice cap, and the Hall of the Astronomicon [[RefugeInAudacity was carved out of the interior of Mount Everest]]. Unlike many settings' hive cities, the value of Terra is not as a trade hub, but as the slow-beating administrative heart of the Imperium and the holiest of religious sites.
** There's also Cammoragh, the ''city dimension'' of Dark Eldar, which supposedly dwarfs imperial Hive worlds in size. Supposedly, because it's an extra-dimensional conglomerate of megapolicies, arranged in a way that [[AlienGeometry defies all common sense]]. It's also arguably the most evil place in the galaxy, and that's saying A LOT in 40k.
* Sprawls/metroplexes in ''TabletopGame/{{Shadowrun}}''.
** Like much of the Shadowrun universe, these are most likely inspired by William Gibson's work, outlined above.
* Mort City in ''TabletopGame/SLAIndustries''. [[UpToEleven which, we feel we should stress, is roughly the size of Eurasia.]]
* Though there have been many cities mentioned in ''TabletopGame/MagicTheGathering'', none quite so massive as the plane-spanning city of guilds, Ravnica. A city so big, it has all five mana-producing lands contained within it with room to spare. A city so big, it took ''[[http://wiki.mtgsalvation.com/article/Category:Ravnica_block two]] [[http://wiki.mtgsalvation.com/article/Category:Return_to_Ravnica_block blocks]]'' (at three card sets per block) to cover it all.

[[folder:Video Games]]
* Mega-Primus in ''VideoGame/XCOMApocalypse''. According to the {{backstory}}, it's actually the prototype of the concept designed to consolidate the remaining living space on the planet following the aversion of NoEndorHolocaust at the end of ''[[VideoGame/XCOMTerrorFromTheDeep Terror from the Deep]]''.
* One of the playable locations in ''VideoGame/MassEffect3'' is a city representing the unification of Vancouver and Seattle.
* Kaineng City from ''VideoGame/GuildWars Factions''.
* One of the ultimate goals in any ''VideoGame/SimCity'' game is to reach as high a population as possible. In the original game, reaching a population of 100,000 would upgrade your city into a Metropolis. Reaching 500,000 citizens meant that your city be classified as a Megalopolis.
* Mute City in ''VideoGame/FZero''. Formerly called New York City (according to the anime), it grew to a population of over two billion people and aliens.
* ''VideoGame/GranblueFantasy'' has the Erste Empire's capital island, Agastia, which is a gigantic sprawling city and military complex that occupies the entire island with little greenery to be seen.
* One of the locations in ''VideoGame/DreamfallChapters'' is Europolis, a dystopian Stark city covering most of Central and Western Europe.
* ''VideoGame/TheMatrixPathOfNeo'' has the pre-war human Mega-cities during cutscenes.

[[folder:Web Comics]]
* ''Webcomic/GunnerkriggCourt'': The court itself has gigantic proportions, its full size has yet to be revealed.
* ''Webcomic/{{Shifters}}'': The comic takes place in Shade City a Mega City that encompasses a vast amount of territory in the Pacific Northwest.

[[folder:Western Animation]]
* In most series, [[Franchise/{{Transformers}} Cybertron]] is about as large as the Earth, all the way up to the size of ''Saturn'' in some series. Despite this, most of it's cities aren't just ''visible'' from orbit, they're so large they visibly alter the planet's silhouette. Population tends to be smaller than one might think, given that the average [[TransformingMecha native]] is around 20-30 feet tall and the infrastructure is accordingly scaled up.
* ''WesternAnimation/AvatarTheLastAirbender'': The Outer Wall of Ba Sing Se seems to encompass nearly 10% of the land area of the largest continent on its planet, and its population is equally gigantic, especially in comparison to those of the entire Air Nomad and Water Tribe civilizations.
* Metropia in ''Westernanimation/{{Phantom 2040}}'' is a self-governing {{city state}} of 32 million inhabitants - that's over 10% of the entire population of America at the time it was made.

[[folder:Real Life]]
* The proper term to describe cities -- more specifically, broad-stroke regions -- that have reached extreme levels of population and urban development is ''[[https://en.wikipedia.org/wiki/Megalopolis_(city_type) megalopolis.]]'' A [[https://en.wikipedia.org/wiki/Megacity megacity,]] on the other hand, is typically defined as "a metropolitan area with a total population in excess of ten million people". While there is considerable overlap between the two terms, a crucial difference is that a megacity can be a single metropolis, while a true megalopolis comprises a '''chain''' of highly interlinked metropolises. The following examples listed below all qualify as megalopolises, as most of them are a chain of metropolitan areas that are so closely connected to each other that they have begun to overlap.
* The metropolitan area of Jakarta, the capital of UsefulNotes/{{Indonesia}}, houses 30 million people, slightly less than the total population of the country's neighboring ArchEnemy, UsefulNotes/{{Malaysia}} (32 million). And you can't dismiss Malaysia as a small country either; 127,724 mi2, compared to Metro Jakarta's 6,615 mi2. Were it a country of its own right, it would be the 45th most populous in the world.
* There are about as many people in UsefulNotes/{{Tokyo}} and neighboring cities as there are people in [[CanadaEh Canada]], which makes the TokyoIsTheCenterOfTheUniverse trope feel juuuuust a little bit {{Justified|Trope}}. If Tokyo were a separate country, it would be the 34th most populous in the world, after UsefulNotes/{{Poland}}.
** Speaking of Canada, the Greater Toronto Area (which includes the City of UsefulNotes/{{Toronto}} as well as several other nearby towns and cities of varying sizes) contains over 6 million people and occupies an area of over 7,000 square kilometres. This alone represents about one sixth of the entire population of Canada. With that said, it falls short of the usual definition of a mega city as a metropolitan area with more than 10 million people.
* Keihanshin (Kyoto-Osaka-Kobe) is no slouch either. The figure varies depending on the method, but it is somewhere around 17-20 million people. Unlike other metropolitan regions, however, Keihanshin was unique in that UsefulNotes/{{Kyoto}} and Osaka were (and to some extent, still are) separate cities with separate civic cultures for most of Japan's history. It was only with the rise of modern transport in the early-to-mid 20th Century that the two cities started to form an integrated metropolitan region.
* Although it may not seem like much compared to other entries in this list, UsefulNotes/{{London}} was probably the first modern metropolis with a population of 6.7 million in the 1900s. It is still one and the largest among European cities, with 14 million people living in the [[https://en.wikipedia.org/wiki/London_commuter_belt London commuter belt]] which includes the [[https://en.wikipedia.org/wiki/Greater_London Greater London]] area.
* Speaking of European cities, UsefulNotes/{{Paris}} and the surrounding [[https://en.wikipedia.org/wiki/Île-de-France Île-de-France region]] also counts. 12 million or approximately one fifth of the French population lives in the region, making it the fourth largest metropolitan area within Europe.
* Moscow, by the way, is the largest MegaCity in Europe. The most conservative reckoning of the megalopolis' population is 16.8 million people, not counting unregistered, transient and illegal residents; with them, it could easily top 20 million. The "official" city without suburbs and satellites has 12 million people.
* UsefulNotes/{{Istanbul}}'s metropolitan area, with almost 15 million the second largest in Europe, actually dwarfs the total population of its [[UsefulNotes/{{Turkey}} host country's]] Balkan neighbors, UsefulNotes/{{Greece}} and UsefulNotes/{{Bulgaria}}, which have 10 and 7 million, respectively. Even if you subtract the Asian side of the city, it leaves around 9.5+ million intact, still larger than Bulgaria.
* In the US (and other places), urban sprawl has started expanding cities to the point where they run together. For instance:
** The first was known originally as [=BosWash=] (sometimes [=New BosNYWash=] given UsefulNotes/NewYorkCity is a big percentage of the people), a near contiguous mass of cities and suburbs running from UsefulNotes/{{Boston}} to UsefulNotes/WashingtonDC. Currently the cities in this area have yet to fully coalesce, although New York City/North Jersey/Fairfield County (CT) and UsefulNotes/{{Philadelphia}}/Camden (NJ) are close, as are Boston, Worcester (MA), and Providence (RI). [[note]]The fastest growing area in Massachusetts is the corridor of outer suburbs between Route 128 and I-495 known collectively as [=MetroWest=], while Route 1 between Boston and Providence is essentially one long commercial strip anchored by the Automile in Norwood (just off 128) and Gillette Stadium in Foxboro, somewhere in the middle.[[/note]] Likewise, the DC area spills over into northern Virginia and Maryland, to the point of sometimes being grouped with UsefulNotes/{{Baltimore}}.
** The UsefulNotes/LosAngeles metropolitan area is currently the largest (in terms of area) metropolitan area in the United States and the second most populous, with more than 15 million residents.
*** The coastline of Southern California is essentially this. Driving on Interstate 5 from the US-Mexico border at San Diego all the way to the Interstate 210 interchange in north San Fernando is about 140 miles of urban scenery. The total distance is really about 160 miles, but 20 of that goes through a nature preserve in Camp Pendleton.
** The UsefulNotes/SanFrancisco Bay Area (in California), depending on where exactly you draw the boundaries, comprises up to 8.5 million people and is potentially the 2nd-largest metropolis in the United States - after the Los Angeles area - with a steadily growing population from immigration into the region. It's a well-networked mesh of cities, suburbs, and large towns that surround the SF Bay, and continue to extend outward from there.
** South Florida (the metropolitan area based around UsefulNotes/{{Miami}}) is a continuous strip of connected cities running 110 miles, though never more than 20 miles wide. It's the longest unbroken strip of urbanization in the United States and is home to over 5 million people.
** The UsefulNotes/DFWMetroplex of Texas has about 6.5 million inhabitants living in well over 200 individual towns and cities, the largest metropolitan area in the Southern United States. It is generally split between two main divisions, the Dallas-Plano-Irving group and the Fort Worth-Arlington group, but they're all close enough that it hardly matters.
* UsefulNotes/MexicoCity. Depending on who asks, the population ranges between 20 and 22 million people. That's more than the entire population of some Latin American countries like Chile.
* Basically any city and conurbation in UsefulNotes/{{China}} People's Republic is a megacity by default, simply due to the humongous population of the country. Due to this aforementioned population, though, China also averts TokyoIsTheCenterOfTheUniverse, as the 1.3 billion+ head count can't physically crowd themselves in one corner, but instead have to spread out of the land area.
** There are very large cities in China such as Shanghai (20 million) and Beijing (17 million), as well as a number of large cities in the Pearl River Delta such as Shenzhen (12 million) and Guangzhou (16 million). Take note that the delta is also the location of UsefulNotes/HongKong (7 million) and UsefulNotes/{{Macau}} (650,000, but its status as China's Las Vegas means that the headcount swells up every other time), so the locals of the delta really don't have to go anywhere else in the country to find services. And yes, it [[http://www.telegraph.co.uk/news/worldnews/asia/china/8278315/China-to-create-largest-mega-city-in-the-world-with-42-million-people.html may one day merge to form the largest mega city in the world]].
** Foreign media often neglects the differences between a city proper and a [[http://en.wikipedia.org/wiki/Prefecture-level_City City-Prefecture unitary authority]], resulting in plain wrong statements. The prefecture is often much larger and populous than the city proper of the same name, comparable to a small European country.
*** When Chaohu prefecture (population 4 million) was dissolved, there were news stories claiming a city as large as Los Angeles suddenly disappeared from the map. The Chaohu city proper (not really annexed but now a county-level city belonging to Hefei prefecture) has a population of about 800,000.
*** "World's most populous" Chongqing Municipality is a merger of 4 former prefectures, has a population of 29 million, and is larger than Scotland. The real city proper of Chongqiong has 8 million residents.
*** "World's biggest by land area" Hulunbuir, Inner Mongolia is even larger than the entire UK. This city-prefecture contains several counties and other cities (as the norm); the real city proper (Hailar District) occupies 0.5% of the total land, and is not big by Chinese standards.
*** The above figures for Beijing, Shanghai, Guangzhou, Shenzhen are similarly inflated, as a prefecture may have many rural counties. Nonetheless, their urban areas are large on their own. If you count people regularly residing (as opposed to only those who have Hukou, which is official permanent residence and entitles you to full social benefits of such a city), then Beijing and Shanghai already have over 20 million people in the city proper (as of 2014).
*** Shanghai Metro has crossed the Shanghai-Jiangsu province border with stations in Huaqiao, Suzhou Prefecture, Jiangsu (not Suzhou city proper, but easily reached by Suzhou city bus). Downtown Suzhou is 80km away from Downtown Shanghai.
*** As of February 2014, there are no counties left in Southern Jiangsu and only one in Shanghai (the distant Chongming Island). All such areas, home to over 53 million people, are city districts or county-level cities, although many suburbs are not meant to be completely urbanized. This does not even include cities on the north bank of the Yangtze (Central Jiangsu) or further south (Northern Zhejiang) where urban areas are not large enough to touch each other but still heavily connected via numerous expressways (not to mention high-speed rail).
*** Guangzhou have effectively integrated neighboring Foshan (which is 20 km away from downtown Guangzhou, administratively still a separate prefecture-city), and the larger Pearl River Delta, not only Shenzhen, is also urbanized and interconnected similar to above. (It even includes Hong Kong despite border controls, with Shenzhen Metro and Hong Kong MTR connecting at checkpoints.)
* Mumbai and Delhi/New Delhi in India have populations of over 20 million and over 15 million respectively.
* There are the two largest metropolitan cities of Africa: UsefulNotes/{{Cairo}} (20 million people when you include Giza and the suburbs, which you should) and Lagos (12 million).
* UsefulNotes/{{Seoul}} is also this. In fact, half of the population of UsefulNotes/{{South Korea}} resides in the [[https://en.wikipedia.org/wiki/Seoul_Capital_Area Seoul Capital Area]] (25.5 out of 51 million) with 10 million of them in Seoul, making it one of the largest metropolitan area in terms of population. Its semi-affectionate nickname as the "Republic of Seoul" isn't completely unfounded when you consider that most of your extended family probably live somewhere in the area.
** The [[https://en.wikipedia.org/wiki/BUG%27s Busan-Ulsan-Gyeongsangnamdo metropolitan area]] isn't as large as the Seoul metropolitan area, but it still houses 8 million people, making it the second largest metropolitan area in South Korea.
* Another East Asian state, the de facto nation UsefulNotes/{{Taiwan}}, also has one, the [[https://en.wikipedia.org/wiki/Taipei–Keelung_metropolitan_area Taipei metropolitan area]] with 7 to 9 million people.
* The fertile valleys of the Nile, Tigris, and Euphrates rivers allowed Babylon, [[AncientEgypt Thebes, and Alexandria]] to each become a MegaCity at different points in history, at least by the standards of their time. Later, grain brought in from all over the Mediterranean (including the aforementioned Nile valley) allowed AncientRome to do so.