Advanced Ancient Acropolis

In the dark heart of Africa lies the Shining City of Wakanda. …what? It's night time!

"Explorers searched for it for centuries: El Dorado, the Golden City. They thought they would find it in South America, but it was in Africa the whole time. A technological marvel. All because it was built on the most valuable metal known to man. Isipho, they called it. The Gift."

— Ulysses Klaue, Black Panther (2018)

The development and advancement of human civilization has been greatly spurred by tech sharing (or spying) between cultures and peoples as ideas are traded. While some have advanced socially, culturally and/or technologically faster than others thanks to internal stability and enlightened rulers, it's rare for a single society (much less city-state) to advance leaps and bounds ahead of its neighbors while keeping all its advances to itself.

Except in fiction, that is.

A common setting in pulp stories is the search or surreptitious discovery of an Advanced Ancient Acropolis. Hidden beneath the Earth in a Lost World, an Atlantis under the sea, or concealed with advanced technology or magic, the Advanced Ancient Acropolis is the last city of an empire that reached space age levels of technology and/or mythic magical powers. In some cases, it is an isolated city-state rather than one of an empire. Their claim to fame is that while the rest of the world was living in mud huts they had built a society of Crystal Spires and Togas and parked it in a Medieval comfortable Technological Stasis. All while never revealing its existence, though ancient legends of The Time of Myths may speak of them.

Bonus trope points for avoiding all social decay while being completely insular, double bonus if they use Cultural Posturing on the "inferior" civilization the heroes hail from. One common variation has the Advanced Ancient Acropolis be in the same abandoned and ruined state as the one in Greece, having been destroyed, abandoned, sunken, buried, wrecked from civil war, plague or some other misfortune. There might however be a last survivor in the form of a robot, golem, ghost, or immortal citizen. Sometimes this may expand to include the descendants of the original culture who have regressed into a simpler stage and scavenge in their ancestors' ruins. Heroes visiting these sites are advised that any ancient relics found are likely of the dangerous cursed or Lost Superweapon varieties.

Of course, all of this can be explained if the founders of the city were aliens or from a Higher-Tech Species, or the survivors of a cataclysm that reduced the rest of the world to a lower level.

Common deconstructions frequently focus on just how decadent and out of repair such a society can become, which may in fact be what leads to their ruin. Frequently, this is because their slave race of robots (or actual slaves) rebelled.

See also Schizo Tech and Advanced Ancient Humans. Compare City of Gold and Temple of Doom. A specific form of Older Is Better.

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Examples:

Anime and Manga

• Chrono Crusade: In the manga, the demon world Pandaemonium has technology leaps and bounds ahead of humanity. Of course, this is because Pandaemonium is actually a giant living spaceship under the ocean and the demons are actually aliens.
• The Mykene from Mazinger Z and Great Mazinger inhabited the Greek island of Bardos in ancient times. Their technologic level was miles ahead of any other culture of the same time, and the rest of the world would need millennia to catch up. However, one earthquake shook their island and destroyed their cities, and they were forced to seek shelter underground. They founded another civilization Beneath the Earth, but on the surface the only remainder left of their presence were abandoned, decaying ruins, and old legends about the Humongous Mecha they used to defend their land.
• The Mysterious Cities of Gold: Nearly every temple pyramid that Esteban and his friends discover has some sort of solar-powered mechanism left behind by the ancient empire of Mu. One of them even serves as an aircraft hangar for the Golden Condor, while another is both a giant solar laser and the containment system for a fusion reactor.
• Nadia: The Secret of Blue Water: Atlantis used to be one of these, but by the time the main characters see it there's nothing left but wreckage. A few smaller, better-preserved outposts are subject to the Archaeological Arms Race that drives much of the plot.
• One Piece: Although few details are known, there was an ancient civilization destroyed by the World Government that seemingly created some of the most powerful weapons that history's ever known, each one capable of destroying the world.
  • In the Egghead Arc, Shaka/Dr. Vegapunk reveals that there was once an extremely technologically advanced ancient kingdom which existed 900 years ago in the past. Whether it's the same kingdom of the example above or not is unknown.

Comic Books

• The DCU:
  • In the Superman story Kryptonite Nevermore, a mystical object called the Devil's Harp and other strange artifacts were discovered buried beneath an ancient, forgotten, unnamed city.
  • Paradise Island, the Wonder Woman (1942) pre-Crisis home of Wonder Woman and the Amazons, has healing rays, invisible aircraft, and telepathic videophones (after all, they were a scholarly race of virtual immortals with a scrying device for observing the progress of the outside world, and nothing but time on their hands to invent things). Themyscira, the Post-Crisis Wonder Woman (1987) and Wonder Woman (2006) version, isn't quite so advanced originally, though it did "avoid all social decay"; later writers and retcons would restore much of the tech of the Golden and Silver Ages.

Films — Animated

• Atlantis: The Lost Empire. Although by the time Milo and the crew gets there, the natives have forgotten how everything works.
• Ice Age: Continental Drift ends with Scrat finding himself in such a setting, full of squirrels wearing togas, studying mathematics and debating philosophy in a setting of classical architecture and statues of acorns.
• Ultimate Avengers: Wakanda, as in the comics. Looks like a very tiny central African nation with an extreme "no outsiders" rule, slightly more justified than usual given they've spent sixty years fighting off aliens who want their vibranium (since it's the one thing that can kill them). Then when the aliens attack, out come the giant laser guns.

Films — Live-Action

• Black Panther (2018) brought Wakanda to the big screen for the first time. However, it was deconstructed as well: Killmonger, and his father N'Jobu were angry that they, along with millions of other Africans and African descended peoples, had to live in poverty and oppression while the Wakandans lived in decadence and did nothing to use their resources to help out the others. By the end of the film, T'Challa has promised to use Wakanda's resources and technological superiority for good, by opening a Wakandan outreach center in Oakland and revealing the true nature of Wakanda to the United Nations in The Stinger. Plus there's the fact that for all the advanced technology of Wakanda it is still a rather conservative tribal confederation, with all the inherent problems — Feuding Families, Asskicking Leads to Leadership, We ARE Struggling Together, etc.
• Some of the surprisingly-advanced Bamboo Technology beyond modern inventions and durable death Traps in Congo.
• Indiana Jones and the Kingdom of the Crystal Skull. In Frank Darabont's unused draft, the technology was even more advanced than what was seen in the film.
• In King Kong (2005), much of Skull Island's "landscape'' is actually this trope: the monumental structures, roads, and statuary left behind by a long-vanished human culture. Their only descendants have degenerated to a state of barbarism, and their architectural works and carvings have been reduced nearly to rubble by the jungle, cyclones, earthquakes, and neglect.
• In Planet of the Apes (2001), the Holy City of Calima turns out to be both ancient and advanced since it's actually a starship from Earth that crashed centuries before.
• She (1935) and She (1965) have the ancient city of Kor — in the Arctic Circle and in Africa, respectively.

Literature

• An Older Than Radio example occurs in Kurd Laßwitz's 1882 short story "Apoikis". The narrator by chance comes to an uncharted island in the South Atlantic which is home to an advanced Greek city-state called Apoikis, which was founded by philosophers who emigrated from Greece after the execution of Socrates. Because they did not go through the Dark Ages and other reverses in the march of civilization, the Apoikians overtook European civilization in fields that interested them, particularly philosophy and the mind (most people who come to their island will be made to forget) and also beyond ancient Greek society (there are no slaves and an Apoikian woman is horrified to hear that in Germany girls are not taught ethics and logic in school). They dispose of futuristic technology, such as submarines and an impenetrable force-field, but are perfectly content to live among themselves and away from the barbarians of the outside world most of the time.
• In Catseye (1961), Ruhkarv was left behind by Forerunners. The one attempt to dig there led to disaster.
• Dinotopia has the lost civilization of Poseidos, which in its heyday had robot dinosaurs, remote control drones, computers, and all sorts of other Schizo Tech.
• Clark Ashton Smith's Hyperborea cycle, set Just Before the End of The Time of Myths, chronicles the history of a few cities like this, and the wizards, poets, and warriors that populated them. We see the original capital city, Commoriom, both before and after its decline and ultimate abandonment for the more southerly Uzuldaroum, but Smith reminds us that both cities now lie buried under Arctic ice.
• The Everlasting Dynasty from Emperor Mollusk versus The Sinister Brain is the oldest living civilization on Earth, having once ruled most of the planet because of their technological superiority, only for time to cause the empire to collapse (as all civilizations do eventually), what remains being a small nation near Egypt. At the end of World War II, the fledgling Axis Powers tried invading them for their technological resources, only for their armies to be curb-stomped by the Dynasty's super-weapons.
• In Shane Johnson's novel Ice, two stranded astronauts find an advanced moon base built by humans from before Noah's flood. The technology is far beyond anything they've seen.
• In Ice Crown, the promise of Forerunner ruins motivates the mission to Clio, even though they are forbidden to make contact with the natives and have to do a lot to avoid it.
• H. P. Lovecraft:
  • At the Mountains of Madness features an example of this, notably of the alien civilization subtrope. It's an empty metropolis in the heart of Mysterious Antarctica.
  • One of Lovecraft's short stories, "The Nameless City", is set in a forgotten ruin somewhere in the Arabian desert. The narrator gradually realizes that the city's original denizens were not human.
• Oathbringer: Subverted; the acropolis in question, Urithiru, is nine thousand years behind the rest of the planet in Magitek. Possibly zig-zagged; the principles in use are the bare fundamentals taught to all artifabrians but applied on a city-wide principle, making up in scale for what it lacks in sophistication.
• In the Realm of the Elderlings series, there's Kelsingra and several other ruined ancient Elderling cities found on the banks of the Rain Wild River and only accessible by using a liveship or taking the long, Skill-wrought road leading there from the Mountain Kingdom. Due to their proximity to and co-habitation with dragons the Elderlings were able to take advantage of the latter's magic and develop what amounts to Magitek, yet their cities were destroyed in a cataclysm so devastating it changed even the course of the coastline.
• Rogue Moon by Algis Budrys centers around a mysterious (and deadly) labyrinth left behind on the moon by long-absent aliens.
• She has the ancient city of Kor in Africa.
• The Noldor domains in Beleriand and Númenor of the Dûnedain in The Silmarillion.
• A Song of Ice and Fire:
  • From what we hear about it, Valyria sounds like an unusually advanced civilization in the medieval setting of the series. Its city was said to be dominated by topless towers, and it produced a lot of cool inventions (notably, Valyrian steel) that have never been successfully replicated after the Doom swallowed most of them.
  • Asshai is one of the oldest cities in the world, but it is so ridiculously huge that it can hold the next four largest cities combined within its walls, suggesting that it was built as a gigantic city from the very beginning, although its current population is no larger than a market town.
• The Witchlands has the city of Lovats, which has several features that leave its current occupants scratching their heads. Most notably, the city sits on top of several giant rivers and a waterfall, and the only way to access it is a set of enormous, indestructible bridges. It also has a sewer system that's possibly bigger than Lovats itself and may host an entire Underground City of its own.

Live-Action TV

• The Babylon 5 setting in general, including its Spin-Off Crusade, is littered with the ruins of civilizations that died out millennia ago, so much so that the MegaCorp Interplanetary Expeditions can turn sizable profits from mining them for Lost Technology. They're often plot points, too: Sheridan's wife was killed (not really; she was capture by the Shadows and brainwashed) investigating Z'ha'dum.
• Numenor in The Lord of the Rings: The Rings of Power. Its existence is insular, and not even Sauron did not expect a kingdom of Men to be the most advanced civilization in Middle-earth..
• Played straight and then subverted in Stargate SG-1. Our heroes discover references to the lost city of Atlantis and set out to find it. They think they've found it buried under the ice in Antarctica, but eventually they figure out that Atlantis is in another galaxy — setting the stage for the spin-off series Stargate Atlantis.
• Wonder Woman (1975): Paradise Island is an uncharted island within the devil's triangle. In 1942, the amazons wear togas and use bows and arrows, but they had an invisible plane, a truth serum, and guns to use in her "Bullets and Bracelets" challenge.

Pinball

• Congo has Zinj, the hidden city filled with Killer Gorillas.

Podcast

• You explore the ruins of what might be Atlantis in the Twilight Histories episode “Isle of the Lost.”

Tabletop Games

• Two sorts appear on Mars in Rocket Age. There are ruined cities, still with some technology working, and the modern cities that endure to this day. The modern cities often still have access to advanced technology, but barely understand it or use it well.

Video Games

• Many 4X- and Grand Strategy Games may make the player (or at least in theory other AI players) advance way beyond their neighbors, more so than realistically possible.
  • In the Civilization series, one civilization can be building a star ship to the next system while others are still fighting with axes and haven't even discovered the wheel.
• Assassin's Creed games have ancient temples all over the globe built either by the First Civilization, Templars or Assassins, usually hiding Pieces of Eden. These temples have complex mechanisms such as hidden platforms and doors despite some of them dating as far back as the period of Adam and Eve.
• Inverted with the city of Shinto in Asura's Wrath as well as the rest of the Shinkoku Trastrium civilization. All the buildings and sculptures fit the look of Ancient Hindu and buddhist buildings and sculptures that would seem far too advanced for their time, but in a twist, the story takes place several thousands, if not millions of years in the future that merely is made to look like an ancient civilization.
  • The DLC ending reveals that the game in fact took place 870 million years in the past!
• BioForge: The Phyxx base, the last relic of this advanced alien civilization, found on a distant moon.
• Columbia in BioShock Infinite is a single city that is apparently advanced enough to wage war against the rest of the world. It stole most of its inventions through Tears in reality that allowed them to see possible futures. This is how they gained Vigors; by stealing them from Rapture
• Chrono Trigger: The Kingdom of Zeal includes floating cities and other advanced technologies, and is more advanced than any civilizations that would follow for thousands of years.
• Child of Light: Some locations in Lemuria give off this vibe, with magnificent structures and palaces worn down by time. Ancient writings hint that the ancient Explorers built cities long ago, but they were since abandoned and decayed. The Temple of the Moon contains an elaborate labyrinth said to be built by Erin. More notably, Cynbel Sea contains a brilliant icy temple, which holds what looks like an electrical generator, and even deeper within is the magnificent Palace of the Sun.
  Aurora: This prison seems ancient. Who made it?
  Oengus: Some say Erin, the explorer
  Who hailed from distant shores.
  Lemuria founded by the four.
• Atlantis, again in Ecco the Dolphin, where the Atlanteans invented a time machine and escaped into the past when their city was destroyed.
• In The Elder Scrolls, most prominently seen in Morrowind and Skyrim, the former cities of the Dwemer are this along with being Underground Cities. Since the Dwemer mysteriously disappeared thousands of years ago, their cities have fallen to ruins. However, the Dwemer were extremely technologically advanced, with their creations unmatched by any other group in the thousands of years since. They were masters of combining enchantment-based Magitek with Steampunk machinery, and were known to bend the laws of nature and physics to make their creations last. It is all now Lost Technology, and their ruins still have Eternal Engines running and Mecha-Mooks on patrol. Their citadels around Red Mountain in Vvardenfell, the former epicenter of Dwemer culture, and Blackreach, the former Dwemer capital of Skyrim, are especially massive and advanced.
• The Final Fantasy series likes this trope:
  • Final Fantasy: The flying fortress in the original NES version was obviously high-tech and patrolled by the Warmech, a robotic enemy. Later versions gave it a more medieval look.
  • Final Fantasy IV: The Crystal Spires and Togas Lunarian city.
  • Final Fantasy V: The Ronka Ruins were highly advanced, considering that upon activation they began to fly with the Crystal of Earth and had teleporters and anti-air cannons installed. They also created the airship maintenance base Catapult.
  • Final Fantasy VII: The ruined City of the Ancients is eerily advanced-looking despite predating the entire human civilization.
  • Final Fantasy VIII: Centra. The existence of static remnants of their civilization is justified by the setting; every so often for the past 10,000 years, a swarm of monsters falls from the moon, and this event (dubbed the Lunar Cry) has enough destructive power to obscure entire civilizations suddenly, even in an advanced state.
  • Final Fantasy X: All over the place. The two main examples are huge subversions of the usual trope.
    • Bevelle is a living city that abandoned its Lost Technology for religious reasons. Except that they didn't.
    • Zanarkand is the summoned dream of an ancient, lost technological civilization created to preserve its people in the face of a war of extinction.
  • Final Fantasy XII: A downplayed variation; the world of Ivalice was certainly once in the throes of a major industrial revolution, and almost all technology in the setting is of modern innovation, but the ancient ruins in the game have teleporters. No one in the party really knows how they work nor cares for that matter. It's just something they expect ancient ruins to have.
    • Ivalice games that are set after FF 12 probably have that game to thank for their examples. The Clockwork City of Goug is a Moogle city in Final Fantasy Tactics A2 in which old technology is excavated, and new technology is created. Long in the future in Final Fantasy Tactics, it's also a city where ancient machine relics are dug up and examined.
  • Final Fantasy XIV: XIV's world has layers upon layers of ancient civilizations buried on top each other, each rising up and being wiped out in cycles known as Astral and Umbral Eras. The most prevalent of these was the Allagan Empire, a space-age civilization that rose and fell in the 3rd era (for reference, the game is mostly set in the 7th). Allagan technology, and the discovery and subsequent reverse-engineering of it (often by the antagonistic Garlean Empire), is the impetus for much of the game's story.
    • Expanded upon in Shadowbringers when the player learns that much before than even Allag, the Ancients lived a perfect utopia called Amaurot, a mega city with skyscrapers and art deco architecture, who didn't know anything but peace and love for their world. They had control over "creation magic", indulging in new ideas and concepts to materialize. By trying to stop the cataclysmic "Final Days", the world was shattered in 14 pieces, one of them being the "Source" where most of the game's story takes place. The Ancients -except three of them- also had their souls fragmented, turning into the new, not powerful inhabitants of the world and its reflections, unaware of their past. The city of Amaurot in the Source is theorized to be completely destroyed due to countless world changing calamities, while its reflection in the First was also ruined by time on the depths of the ocean. In the end of the expansion, the hero explores a memory version of the city, a mirage made reality by the unshattered ascian Emet-Selch, frozen in time shortly before the Final Days, where he and his companions are interestingly mistaken for children by the spectral citizens.
• Fire Emblem: Three Houses has this, in a first for the franchise. The lost civilization of Agartha, a technologically advanced nation millennia ago grew arrogant and waged war against the goddess Sothis, who paid them back by wiping out Agartha. Unlike most other examples of this trope, Agartha continues to exist into the present day via the descendants of the survivors of the war, who live in a secret Underground City known as Shambhala. And to top it all off, the Agarthan descendants (now known as "Those Who Slither in the Dark"), are still dedicated to their war of extermination against the goddess and her Children, and they still possess a good chunk of their ancestors' advanced technology and know how to use them: besides living space, Shambhala is also host to a battery of long-range missile silos, and is heavily defended with electrical cannons and Humongous Mecha armed with massive swords that shoot out energy beams.
• Golden Sun: The Lost Age uses Lemuria, which was formerly the most advanced civilization in Weyard. After the powers of Alchemy were sealed by the lighthouses, the island closed itself off in an attempt to keep the remaining alchemy to themselves. Lemuria makes for an interesting case because, like the traditional Elf village setting, the citizens live for a very long time, and many of them deny that any decay has taken place at all. The king, however, shows the player's party maps of the world prior to the sealing of Alchemy and after, and there's a visible level of decay on a continental scale. This actually serves as a major turning point for the game.
• The isolated citadels of the ancient Jotuns in Guild Wars 2 can be considered this. Located high in the mountains, they were created by the highly-advanced Jotun culture before their civilization tore itself apart.
• Atlantis, of course, in Indiana Jones and the Fate of Atlantis, the cinematic game with half human hybrids and Bronze Age Orichalcum-powered Lost Technology.
• Played straight with Atlantis in The Journeyman Project 3. While El Dorado and Shangri-La were somewhat advanced in comparison to neighbors, Atlantis was a self-contained city-state that enslaved the crew of any ship that discovered their location.
• La-Mulana and its sequel are entirely composed of this, with many of the ruins housing sophisticated lost technology from various ancient civilizations. The reason for the fall of each civilization is eventually discovered: The Mother, an ancient alien which the ruins are inside of, created each race to find a way to end her misery. When each in turn could not, she destroyed them and created another.
• Justified in Phantasy Star IV. Any ancient civilization dug up and studied in Motovia were built and controlled in Phantasy Star II by the hyperly advanced alien AI called "Mother Brain", which had been designed to provide convenient and somewhat lazy life for humans as the villain's gradual poison apple plan to dominate the planet. When Mother Brain was killed by the heroes at the end of the game, Motavia's global system malfunctioned, and the planet's civilization was reverted back to the Desert Punk society it used to be.
• In Phoenotopia, humanity on Earth recovered after the ancient war, and ancient Earth is seen as one of these. Expanded on in Phoenotopia: Awakening, where those sites are actively being kept secret by the Peace Ministers (with the aid of several different royal dynasties) in an effort to control the advancement of technology and prevent another war.
• In The Savage Empire, the Kotl civilization is a Mayincatec civilization with advanced technology.
• There are several signs of the advanced Echidna civilization on Angel Island in the Sonic the Hedgehog games, but the most technologically advanced is the Sky Sanctuary which is in the clouds and has teleporters.
• The Xel'Naga temples in StarCraft
• In Tales of Phantasia, the ancient city of Odin was more or less on par technologically with Earth in 1994, and even looked like a modern metropolis. It suffered a major universe-appropriate WMD-style cataclysm and ended up buried, but reasonably intact. Contrast with the mostly medieval style of everything else in the world.
• In Tales of Vesperia, the ancient Kritya society invented the Blastia, but were wiped out by an apocalypse. The player even visits a Krityan ruin early on the where they find some of the only golems in the game.
• Inverted in Team Fortress 2: Australium is an exceedingly rare metal that boosts human abilities far beyond normal, meaning Australia featured 21st-century cities in the 19th century.
• Tears to Tiara 2: Tartetos, an entire city floating in the middle of a lake. Complete with walls light enough to float, but stronger than anything humans can build. The grounds keeper is a Dragon Goddess that looks like a young girl.
• In The Touryst, the Monuments that lend their name to the islands the protagonist enjoys their vacation on are remnants of an ancient advanced society that built many wonders from materials gathered from meteors landing upon the earth's surface. One particular instance is the TOWA Monument, which hides the launchpad of a working rocket-ship!
• Uncharted makes the lost civilizations Shambala (Shangri-La) and Ubar (Iram of the Pillars) the objectives of the second and third installments. The first game involves El Dorado (the legendary lost City of Gold) but reinterprets the legend (turning it from a lost city to a golden idol).
• A Very Long Rope to the Top of the Sky: Genevieve's history lesson on Ancient Man talks about what little is known of the past, and especially how there was an advanced civilization there:
  What we do know is that a civilization predated our current one. Their technology is incredibly advanced and has had a major impact on our society.
• In World of Warcraft there are a few layers of these lost civilizations: all more magi-technologically advanced than the present day. Of course, there have been a fairly large number of devastating cataclysmic events: which wiped out the old civilizations. These isolated cities crop up several times in game: but the most notable of all is Suramar. Once a grand city in the High Elven civilization, it survived the cataclysmic end of that civilization thanks to a magical barrier. However, the barrier blocked out sunlight and starlight: so another source of energy had to be found: The Nightwell. The citizens grew dependent on the Nightwell for their very survival, and it physically changed them (elven physiology is very responsive to magic). Suramar gets rediscovered in the expansion Legion.
  • Any place where Titan structures remain intact in World of Warcraft is this by default. Most are concentrated on areas of land close to the north and south poles. The dwarves have taken particular interest in these old Titan leftovers after relatively recent discoveries of a connection between their race and some of the old Titan constructed races, and make it a point to try and find and excavate such sites.
• Shevat, its rival Solaris, and Zeboim Civ in Xenogears, though the former two were mostly just hoarding tech from the super-advanced starship that brought Humans to their world in the first place.
• The Floating Continent of Ys in the second game of the series, the Ancient City in Ys IV: Mask of the Sun/Ys IV: The Dawn of Ys/Ys: Memories of Celceta, the lost kingdom of Kefin in Ys V: Lost Kefin, Kingdom of Sand, and the ruined city of Kishgal in Ys VI: The Ark of Napishtim.

Webcomics

• In Dubious Company, Walter comes from a Magitek nation that resembles a mix of modern day and Crystal Spires and Togas and may or may not be Fluffy Cloud Heaven. The rest of the world follows more closely to a Standard Fantasy Setting and Walter has to piece together most of his tech from scratch.
• The titular lost city in Fweeeeetopia is a floating-city-type, staying in the air through massive engines.
• In Tellurion people live or move about buildings or outposts built by precursors as if they're part of the scenery. One group is intent on destroying some of this history, as if people being able to understand it threatens their power. The heroes of the story manage to find access to a secret city anyways.

Western Animation

• More than eight hundred years After the End, the New York City subway serves as the home of the Lich in Adventure Time.
• Mr. Pickles is revealed to hail from an ancient city in North America he and Agnes refer as Pavanatra Sluganotharat. Assuming the latter's statements about Mr. Pickles showing her "their ways" is correct, they had technology such as corpse reanimation engines and space-launching missiles, all while displaying a Heavy Metal barbarian aesthetic.
• In Star Wars Rebels the Sith Temple ziggurat-like pyramid with its Doomsday weapon and the surrounding abandoned ancient city beneath the surface of Malachor.
• In Thunder Cats 2011, Big Bad Sorcerous Overlord Mumm-Ra's Futuristic Pyramid is the long-abandoned variation, with Mumm-Ra as its single Living Relic inhabitant until he begins marshalling his forces. Much more capacious than it first appears, it's inferred as the source of all his army's Offscreen Villain Dark Matter. This is due its origins as a battlestar so massive and populated it housed enough people to invade a planet.

Real Life

• The Imazighen had a civilization in the Hellenistic era (it fell a little after Rome did) that even managed to irrigate the Sahara—well enough to grow dates.
• Akrotiri, an ancient Bronze age city on the Aegean island of Santorini, had been using some highly advanced tech and materials for the era — like paved streets, advanced drainage systems and brass (Orichalcum). It was majorly prosperous and the envy of the Achaean Greeks from the mainland. Its destruction by a massive volcanic eruption in the 16th century BC that also led to the downfall of the Minoan civilization is the most probable origin of the myth of the Atlantis.
• The deserts of Saudi Arabia and the Sahara contain lost cities that are only now being discovered. One city in the deep desert, Iram of the Pillars was assumed to be just a fanciful myth but was in fact a major metropolis with multi-story high-rises completely buried in sand. Another in Yemen is still inhabited.
• Just about every continent contains lost civilizations we know little about because the remains got scattered. Most of ancient Persian architecture and civilization is lost, for instance.
• The Mound Builders around the Mississippi River had elaborate agriculture and trade networks, in support of a chiefdom system probably somewhat similar to feudalism. They fed a population of tens or even hundreds of thousands, despite only using copper for ornaments—they did all that with stone tools (and no wagons). The Mound Builders were so advanced 19th century Anglo-Americans assumed their earthworks must've been the work of Ancient Astronauts or Atlantis, because they didn't believe any Native Americans were capable of that level of engineering.
• The Olmec, best known for their colossal sculptures, probably laid the foundations for all later Mesoamerican civilizations, having innovated the "ball game", civic design, mathematical concepts and agricultural techniques, and probably also a great deal of cosmology (they originated ritual bloodletting, for example, although we have no evidence they actually practiced human sacrifice—that's their successor, the "Epi-Olmec". No one's sure why the Olmec declined, although we can assume they abandoned their urban sites because their decline, whatever caused it, meant they no longer had the resources to maintain cities.
• The Classic Maya, and to a lesser extent the early Postclassic (most famously the Postclassic center Chichen Itzá), had an extremely complex urban civilization and the only decipherable written language in the New World. Lidar scanning done in 2018 indicates the extent, infrastructure, and population of the Mayan Empire to be far larger than originally thought, with the Mayans having likely created the first city in the Americas with a population of over one million. The jungles had concealed the ruins so well that earlier archaeologists just climbed over these hidden temples, neighborhoods, and governmental buildings thinking they were just hills!
• To the Mexica and other Nahuatl-speaking peoples, the city of Teotihuacan, once a giant metropolis that traded with and influenced much of Mesoamerica, but was abandoned by imperial times. In Nahuatl, its name means "Birthplace of the gods." Even more significantly, its Mayan name means "Place of Reeds", which is the homeland of the Aztecs' ancestors, the Toltecs ("Reed-people"). Only, we're pretty sure the people who built Teotihuacan weren't anyone related to the Toltecs, but either the Totonacs (who claim they built it, and the Aztecs agree with them), or, as all the archaeological and linguistic evidence indicates, a Mixe-Zoquean group; more confusingly everyone seems to have been represented in the city, it had distinct ethnic neighborhoods, so it's very difficult to pin down as "a city of the X people".
• Rome's civic works were extremely advanced, the kind of thing only a massive central bureaucracy and the backs of millions of slaves can accomplish without modern industrial infrastructure. Ancient Romans would create giant infrastructural projects, steam-powered toys, and even an ancient mechanical computer was found in a Roman-era shipwreck. Several of Roman cities had much better sewers than Victorian London. For centuries after Rome's fall, its works (which, again, had "empire" resources to play with) were seen as the pinnacle of engineering — even by cultures that had surpassed Rome in raw technical ability, like the medieval French, whose arches were stronger, whose wooden houses had stone chimneys (there was a reason Rome had all those fires).
  • Some of the city of Rome's ancient infrastructure, such as their roads, the water and water waste systems are still used today, at least in part — at least two of the ancient paved roads are still in use and open to the public, the Trevi fountain is still supplied by the Aqua Virgo aqueduct, and not insignificant parts of the modern Roman sewers were in fact built at least 1800 years ago.
  • The book ''De Architectura'' (aka Ten Books on Architecture) by Marcus Vitruvius Pollio, is the first grand manual for aspiring architects … and while the machinery used in building stuff has marched on, the lessons on how to build cities and houses are still so valid that the book is still part of studying civil engineering and architecture.
• The Indus Valley Civilization cities had planned layouts and a sophisticated sewage system 2000 years before the foundation of Rome. The city of Mohenjo-daro is thought to have housed 35,000 inhabitants at its peak.
• The Khmer Empire (modern-day southeastern Thailand, central and southern Vietnam, and the entirety of Cambodia) was all but forgotten in the centuries following its demise until 1861, when Frenchman Henri Mouhot stumbled across the ruins of Angkor Wat deep in the jungles of Cambodia. Later research indicated that the city of Angkor might have boasted a population of more than one million people.
• Neolithic and Copper Age Europe are revealing more and more sophisticated villages and towns, some even featuring walled fortifications and temples. Maidanetske is especially noteworthy as having a total of 1575 buildings, including dwellings, fortifications, sanctuaries, and some two-storied houses. Oh and it was inhabited around 3700-3600 BC some 2000 kilometers northward from the Fertile Crescent. Many archaeologists and historians now believe that it is only a matter of time before we find a civilization as old and sophisticated as the Egyptians or Sumerians and as far away from the places they inhabited as they are away from us time-wise.

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