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Elaborate Underground Base

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JGSDF Soldier: Who are you?
Sam Fisher: I'm the guy who's here to save the world.
JGSDF Soldier: I thought I was the good guy...
Sam Fisher: No, no. You're on the team with the super-secret underground base. I'm the guy breaking into the base. That makes me the good guy.

To maintain Plausible Deniability and hide from magical TV Spy Satellites, any sufficiently powerful or advanced covert organization of heroes, villains, conspirators, or military personnel needs an Elaborate Underground Base to use as their headquarters and hide their Applied Phlebotinum. After the End, or in preparation for The End of the World as We Know It, openly known organizations may elect to move Beneath the Earth as well. And it's a good location for a Supervillain Lair.

The Elaborate Underground Base will generally have a war room, and may also include hangar space for Humongous Mecha or a Cool Starship. Particularly large examples may be the size of an entire city, and might include hydroponics bays for growing food or even actual fields of crops lit by sun lamps. The larger sizes of Elaborate Underground Base frequently serve as an Adventure Town; the smaller ones are frequently the setting for a Bottle Episode. If it was built during the Cold War, it may be Ye Olde Nuclear Silo.

Particularly secretive organizations may hide their Elaborate Underground Base in the middle of a city, and include lots of elevators, trams, pneumatic tubes, and other means of transportation between the base and hidden chambers in buildings on the surface. How exactly such an extensive base can be built in secret (among other things, all the excavated rock and dirt have to go somewhere) is very rarely addressed.

Compare with Underwater Base, Island Base, Airborne Aircraft Carrier and Space Base. Not to be confused with Underground City, which is built by civilians rather than a secretive organization. See Beneath the Earth for a related phenomenon, minus the Applied Phlebotinum. May induce Sigil Spam if the organization really loves their logo.


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    Anime and Manga 
  • Aldnoah.Zero: United Earth Headquarters is a bunker located in southern Siberia that is 600 meters below ground and built to survive a nuclear explosion. Considering the hammer and sickle displayed on one of the hangar doors, it's possible this bunker may be a Soviet holdover from the Cold War. Or, considering the Alternate History, the Soviet Union might not have collapsed and is still the ruling government of Russia. It's large enough to take in thousands of refugees, and transport planes and helicopters have no trouble maneuvering inside.
  • The Guild is a massive developed cave system controlled by Class SSS in Angel Beats!.
  • In Arpeggio of Blue Steel, the Japanese Navy is shown to have an underwater dock at Yokosuka Naval Base, built to protect what's left of the Japanese Navy's fighting ships from the Fleet of Fog. There's also the base I-401 maintained at Iwo Jima.
  • Doraemon: One of Doraemon's future gadgets allows instant creation of one of these. It can be big enough to become a city of its own, which Nobita then exploits to create his own dictatorship (Played for Laughs). However, Doraemon: Nobita and the Knights on Dinosaurs deals with the sinister encounter with Lizard Folk when Nobita and co Dug Too Deep...
  • Father, the Big Bad of Fullmetal Alchemist has the entire area underneath Central city!
  • The Far East Branch of AEGIS in Gate Keepers is found underneath a Japanese high school, because all the Gatekeepers in Japan are teenagers. It has secret entrances in all sorts of places, and the hangar is located underneath the lobby.
  • The Otonashi house in High School Ninja Girl, Otonashi-san is a trap-filled underground lair that is otherwise decorated like a normal home.
  • Mazinger Z:
    • The Island of Bardos. Dr. Hell set his first base in the subterranean mazes of that island, building all that he needed for his Super Villain Lair: a war room for planning strategies, private chambers for his Co-Dragons, barracks for his Mooks, several hangars, laboratories to build weapons, Humongous Mecha and cyborgs, training fields for his troops and Robeasts, his throne room...
    • Dr. Kabuto's lab basement also counts. It was hilariously lampshaded by Kouji in the original manga (since Juzo had built Mazinger Z in his home in the middle of a city whereas his anime version did it in his mansion located in Mount Fuji), when he found the entrance and asked: "Since when is there a basement in the garden?"
    • Great Mazinger: Mykene were a civilization that had lived underground for millennia, so their entire empire — an intricate network of caves and caverns — was an Elaborate Underground Base.
  • Jaburo of Mobile Suit Gundam. As the Earth Federation's military headquarters, it is enormous, having easily enough space for a small city, multiple war factories, and docking space and retractable launch pads for at least a dozen spaceships at once. It’s located beneath the South American jungle, buried so deep as to be impregnable to nuclear weapons, which is why the Principality of Zeon attempted to drop a space colony on it instead. Granted that it's only seen in a few episodes of the original series before being blown away in Mobile Suit Zeta Gundam, but it does get additional screentime in Stardust Memory and MS IGLOO. Its long-forgotten ruins also make a cameo in the finale of Reconquista in G.
  • Neon Genesis Evangelion has NERV setting up shop inside the GeoFront, a massive cavern that is actually just the upper 11% of an even larger spherical cave, which is actually the buried remains of the Black Moon, the object that brought Lilith and life to earth, almost completely filled up with earth and rock debris. Terminal Dogma is an Elaborate Underground Base built below another Elaborate Underground Base.
  • In Overlord (2012), the Villain Protagonist and his forces are headquartered in the Great Tomb of Nazarick, a ten-level complex so big that one of those levels contains an entire forest and a colosseum, and another (the residential area) is basically a small town unto itself.
  • The manga and live-action versions of Sailor Moon have an underground base under the Local Hangout.
  • Numerous Galactor bases on Science Ninja Team Gatchaman fall under this heading. By extension, the enemy bases on the Americanized versions.
  • The Steam Castle in Steamboy is mostly one of these. The surface part of it is large and impressive, but the underground portion is far bigger. The fact that there's a much larger portion underground isn't revealed until it launches and becomes airborne.
  • Super Dimension Fortress Macross/Robotech has an underground base in Alaska (possibly in the site of the real-life Elmendorf AFB), armed with the BFG of Wave Motion Guns. Incidentally, secondary Macross sources list four other identical bases being built when the Zentradi launch the final attack, one of them in the same area of Jaburo.
  • The main characters' HQ in Symphogear. It's probably remnants of a Precursor race.
  • Sgt. Frog has the home base of the Keroro Platoon which is built under the Hinata household, much to the chagrin of Natsumi and Fuyuki.
  • Transformers: Cybertron has the Autobots' base. Mineral deposits prevent sensor scans of any kind from detecting that the terrain has been hollowed, but the equipment had to be painted with a stealth coating to prevent the Decepticons from detecting it.

    Comic Books 
  • Batman:
    • The Batcave, an enormous cave containing a supercomputer, garage, various trophies, and basically everything else the Batfamily needs.
    • Red Robin: Tim Drake is able to build an underground garage, gym, small lab, and workshop for experimenting and making new tech and first aid/medical room beneath the old theater he renovated to live in. Fabian Nicieza and Marcus To stated the only reason it was so elaborate is that the fast-approaching reboot meant they'd never have to try and justify why he could get away with so much construction without blowing his secret ID in-story.
    • In The Attack of the Annihilator, Supergirl builds a whole underground base for Batgirl beneath the streets of Gotham, containing a garage, an armory, a computer, and more.
  • The titular protagonist of the comic book Diabolik has a lot of these, each containing gadgets, laboratories, holding cells, spare Jaguar E-Types and loot while he and his lover Eva live in the luxury homes built right on top of them.
  • G.I. Joe is rife with these. The original Joe base, "The Pit", is hidden underneath the chaplain's assistants' motor pool at Ft. Wadsworth in Staten Island. When this is destroyed by Cobra, a new Pit is built out in the desert. And Cobra has a fair number of secret bases themselves, including an entire town brimming with underground evil.
  • G.I. Zombie: Duke's backers have one of these located under the Rinaldi Spa And Retreat. It's packed with enough weapons to start a war, and also houses an underground garden.
  • In Gotham City Garage, Supergirl, Nightwing and Catwoman break into a secret facility built by Lex Luthor underneath a mountain where he fabricates his army of robotic enforcers.
  • During the Hydra arc of JMS's run on Spider-Man, Peter wonders how HYDRA can build one of these in New York while it's taken the city three extra months to finish a subway extension.
    Unless...this whole thing, it''s...NON-UNION! The horror...the horror...
  • The original headquarters of the Justice League was an elaborate base built into the base of a mountain. Several other teams have taken this base out of mothballs, such as Young Justice.
  • PS238, the school for children of superheroes, is in an Elaborate Underground Base beneath an actual elementary school.
  • Scooby Apocalypse has the Complex, the massive underground lab facility in Nevada where Shaggy and Velma work at the start of the series.
  • In Sonic the Comic the Freedom Fighters used Kintobor's laboratory containing living space, storage areas, monitoring equipment (which left plenty of screens on which to play video games!), a hangar for the Freedom Fighters' biplane, and the mainframe of the Kintobor Computer itself. The Freedom Fighters also expanded the facility in light of their new status as guerillas, excavating further chambers for additional capacity. The most prominent of these was a prison block (less charitably, dungeon), and later Tekno's Workshop the home and workplace of Tekno the Canary.
  • Sonic the Hedgehog (IDW): After the Restoration's headquarters is destroyed during the Metal Virus Saga, the Test Run arc reveals that they've built a new facility beneath the ruins of the old one. Accessible through a hidden elevator, it contains a command center, computer labs, a machine shop, and a central area that's designed like a mall.
  • Strikeforce: Morituri has the team start off with a base hidden inside a mountain. When the alien Horde discover its location, it is destroyed with a nuclear bombardment.
  • Superman:
  • The Thunderbolts have their base located inside a mountain.
  • Wonder Woman Vol 1: Paula von Gunther has a multi-room labyrinth base beneath Holliday College, where she keeps the Space Transformer and works on scientific breakthroughs for the Allies and Wonder Woman. She also lives down there to keep hidden from the Nazis.
  • X-Men:
    • Xavier's Mansion is usually presented as being only living quarters and classrooms for students and staff; the actual base of operations is underground.
    • Lampshaded in Astonishing X-Men #34:
      Cyclops: Our antagonist has serious infrastructure. I have a feeling we're going to see a classic James-Bond-Villain Crazy-Man base make itself known in a few moments.
      Beast: I'm always up for a Doctor Crazy-Pants volcano headquarters.
      Cyclops: This is the bit that really annoys me. All the things in this world that can be fixed with money? And every time it's "Well, I've got all this cash, but I bought myself an asteroid hideout instead."
      Beast: Aaah. That, my friend, is indeed classic.
  • In the Zorro comics written by Don McGregor (for Topps and Dynamite), Zorro has an elaborate underground base that rivals the Batcave. This is appropriate, as the Batcave was actually inspired by Zorro's hideout, both in and out of universe.

    Fan Works 
  • Abraxas (Hrodvitnon): In this MonsterVerse fanfiction, it's been abandoned for decades, but Monarch built a vast underground outpost in the Russian wilderness, which has since been claimed by Alan Jonah and his troops as their new hiding place while they conduct experiments on Ghidorah's severed head and later on the reborn San and Vivienne.

  • Dungeon Keeper Ami features this often and in diverse flavors. The Dungeons themselves, are a little more feudal, but Ami's underground bases just keep getting more elaborate and more Dungeon Punk. Mecha? Check. Underground magical hudrophonics bays? Check. War Room? Check. Sigil Spam? Check. Lacks a proper hangar for the airship fleet, but one was actually an Underwater Base, and another an Island Base...
  • In the Jackie Chan Adventures and Teen Titans crossover fanfiction A Shadow of the Titans, there's the HIVE Academy like in canon, which Jade comments on being like Section 13, only with better aesthetic appeal.
  • Child of the Storm:
    • HYDRA probably had many, but after Operation Overlord and their being forced to retreat to one last base aside from the section of HYDRA within SHIELD, they might have one of these — it's in London, but London's a very big place and no one's actually sure if it's underground.
    • Gravemoss used to have a comfortable lair under the Paris catacombs, but he was forced to vacate it after SHIELD tracked him down and Harry Dresden blew a very large hole in the catacombs and the street above. Now he's living in the basement of HYDRA's last base, which may count if you squint at it a bit.
    • It's implied that the rebuilt MI13's new headquarters is operating out of the abandoned portions of the London Underground network.
  • Examples from The Calvinverse:
    • Dr. Brainstorm of Calvin & Hobbes: The Series used to have one of these, and it gets reactivated by Holographic Retro in "Electric Invasion".
    • The Lightning Man also has one in Las Vegas, and it's lampshaded heavily:
      Hobbes: It's a lair! What is it with bad guys and lairs? Can't they just live in houses?
      Socrates: Imagine a supervillain living in a studio apartment in southeast central L.A. I wonder if they could afford the rent.
    • Calvin's duplicate has one in the Recursive Fanfiction The Pez Dispenser and the Reign of Terror.
  • In Death Note Equestria, there's an old earth pony bunker underneath Ponyville town park that L uses as a base for herself and, later, the Kira investigation team.
  • Jewel of Darkness: Slade, as per canon, has a fondness for these, which Midnight seems to have picked up from him.
  • In the Worm fanfic, Intrepid, the Undersiders get one of these for completing the armored car robbery, with five floors, an indoor park for Rachel's dogs, furnished apartments, a game room, the works. Can't say Coil doesn't splurge on his employees.
  • The Pangea Alliance in the Mass Effect story Mesozoic Effect use these to the point where they don't actually build permanent structures on the surface of their planets. They were originally needed to house the millions of dinosaurs that were waking from their 65 million-year cryosleep, but eventually started building them on other worlds because of their defensive potential.
  • In The Institute Saga, Superman relocates the Fortress of Solitude to underneath the Xavier Institute.
  • The Batcaves in Young Justice: Darkness Falls. Apparently, there were several created, and the team gets one of them after Darkseid's first major attack.
  • In Unity, the facility used by the Anti-Villain League as a headquarters for their new superhero team is a giant underground bunker.
  • EVA Sessions: Someplace Vast and Dry: The NERV Evangelion Center originally started out as a conventional above-ground research center, before gradually transitioning most of its facilities to the canonical underground GeoFront to better protect them from attack by the Others. In this case, the NERV GeoFront is a genuine achievement of human civil engineering, rather than the canonical repurposing of the buried remains of the object that brought life to earth.
  • Tales of the Otherverse: After leaving the Otherverse and settling in another reality, Kara and Rogue set up their new Fortress in Colorado. Above the ground, it looks like a quaint, lonely one-story ranch sitting in the middle of the wood... and above a vast network of caverns housing a grand complex built in the rock.
    This Fortress would be their home... and from the outside, it would appear to be no more than that: a truly elaborate home built in the seclusion of the wood.
    Beneath the elaborate one-story ranch, however, it was another story.
    A grand complex had been carved out beneath the home by Kara and Rogue. Crews from both Stark Industries and LexCorp had been snuck in to install supports and equipment.
    A special entrance and exit tunnel had been carved into one time of the many cavern systems that ran deep in the ground and exited out into the vast lake that bordered the home on the east side.

    Film — Animated 
  • Syndrome has an absolutely awesome underground base in The Incredibles, complete with the '50s-'60s Tiki/Googie/Art Deco look. Eggshell people-movers, yeah! Don't forget, it was built inside an active volcano.
  • Secret Magic Control Agency: The SMCA's headquarters are located in a massive cavern beneath a hair salon. Bridges connect different areas and there are hot air balloons seen inside.

    Film — Live-Action 
  • Dr. Evil from Austin Powers has an underground lair.
  • The Avengers (1998). Sir August's underground base, is on an island in the Thames in London.
  • The HYDRA facilities in Captain America: The First Avenger are above ground and in the open, and their main base is dug into the Alps, and is implied to be 500 feet underground. In addition, the SSR's main base is hidden within various old stores in Brooklyn.
  • The supercriminal Diabolik in the movie Danger: Diabolik has a huge underground lair, to a truly absurd degree for someone who seems to have absolutely nothing in the way of actual henchmen or employees to actually build or maintain things other than Eva.
  • The majority of Day of the Dead (1985) takes place in a vast bunker as the scientists attempt to find a cure for zombies. Less elaborate than most other examples but it gets bonus points for being a real place; it was a mine that was converted for "long-term storage facility for important documents" which is the stuff Ben is looking through in the actual film.
  • The Pit and Cobra's Underwater Base from G.I. Joe: The Rise of Cobra.
  • In Hellboy:
    • The headquarters for the Bureau of Paranormal Research and Defense is located underneath a nondescript government building.
    • Rasputin has an underground lair located under his mausoleum in Moscow
  • Hollow Man has a secret underground lab accessible by a single secure elevator, which Sebastian uses to trap his coworkers.
  • District 13 in The Hunger Games: Mockingjay Part 1, or rather what's left of it as this is how its citizens managed to survive in the first place while topside was blown up. It's implied to have undergone some upgrades as well given that even the Capitol's bombing run does only superficial damage and no casualties.
  • Invisible Invaders: The fallout shelter-slash-laboratory where Dr. Penner and the rest of the cast were placed to find a weakness to use against the titular aliens is as elaborate as Fifties B-Movie budget allows it to get, full of research equipment and with a large garage.
  • The Island: An underground base is used to house clones who are led to believe that the outside is a wasteland.
  • James Bond has very few of these, despite the series being ridden with cartoon villains and conspirators. The closest they ever got was the hollowed-out volcano complex in You Only Live Twice and Drax's Amazon launch facility in Moonraker.
    • GoldenEye had an elaborate underground military bunker at Severnaya, and the Big Bad's Lair is actually below the giant pool where the cradle antenna is hidden.
    • Dr. No had an elaborate nuclear facility but it's not clear that it was underground. Although fairly likely, given that it explicitly is in the book and in the film they dine in a glass-windowed room below the waterline and thus presumably underground as well.
    • Dr. Kananga from Live and Let Die had an underground base near one of his poppy fields in San Monique for processing the poppies' morphine into heroin.
  • Kingsman: The Secret Service
    • The climax takes place in a bunker Valentine has for guarding himself and his guests from the mass genocide he planned.
    • The Kingsman themselves also have a large base and training facility hidden beneath a mansion, complete with a secret monorail and jet hangar.
  • Logan's Run: The city's underground, anything from ruins to a gigantic freezer full of the corpses of the Runners that made it out of the city.
  • Zion in The Matrix that is also a full-blown city.
  • The Megaforce headquarters, a bunker deep in the Nevada desert built to withstand a direct hit from a 25-megaton nuke, with all the necessary elements for training and maintaining and leading the Megaforce, and with a Cool Garage full of extensive military hardware (and Dallas then mentions that said garage is just the one for the ground vehicles, as well as joking about needing $40,000 worth of mops and brooms to keep the place clean).
  • The secret headquarters of the Men in Black are located several stories beneath Manhattan... accessible by the entrance to the Brooklyn-Battery Tunnel.
  • In the sequel to Outpost, another military team returns to the secret Nazi bunker to find the Device missing. They can't figure out where it's been moved, until they find a hidden door to an elevator, leading down to a massive underground complex.
  • Resident Evil Film Series:
  • The Santa Clause franchise has the entire North Pole operation for Santa Claus under an ice pack in the North Pole, large enough to contain the entire Elf village to look like a surface settlement (in Canada, according to the third movie). It remains hidden because Santa and the elves have various strategies to hide it from the outside world. The rest of the world just sees the ice cap and preserves the Secret of Santa.
  • Screamers: The Hunting. The eponymous Killer Robots are made in automated factories beneath the surface. The characters have an Oh, Crap! reaction when they enter a shut-down factory and see just how big it is. Of course, someone inevitably does something stupid to cause it to power up again…
  • Sky Captain and the World of Tomorrow (2004). Mad Scientist Dr Totenkopf has a base populated by hordes of flying killer robots that is large enough to contain a brobdingnagian Raygun Gothic rocketship.
  • Sky High (2005). The Secret Sanctum.
  • Spider-Man: Into the Spider-Verse: The Peter of Miles' universe has one underneath Aunt May's shed, accessed by an elevator, where he keeps alternate costumes, a computer, a lab, and diagrams of criminal connections. Peter B. is noticeably jealous of this, as his base back home just consists of the garden shed itself.
  • In Secret Headquarters, such a location is literally the title. Specifically, it's the Guard's secret hideout, where he keeps all his gadgets and the Source.
  • THX 1138: Doesn't gets more elaborate than an entire underground city.
  • Team America, in Team America: World Police, had an elaborate base inside Mount Rushmore.
  • Undercover Brother. The BROTHERHOOD has an extensive base located beneath a barbershop.
  • In X2: X-Men United the underground base becomes a plot element when the Spy Satellites actually detect the Cool Ship in its hangar underneath the Superhero School. William Stryker uses this evidence to convince the President to okay a commando strike on the school, secretly to further his plan to wipe out all mutant-kind. Stryker's also got an Elaborate Underground Base of his own.

  • The Wildfire facility in The Andromeda Strain. The only entrance is the elevator shed, and the facility topside is what it's disguised as — a wheat modifying facility.
  • The Yeerk Pool in Animorphs spans an entire city. Yeerks need to return there every three days to exit their hosts and absorb the radiation they need to survive, and said hosts are caged in the meantime. There's also enough room for several spaceships and storage areas.
  • In Travis Corcoran's Aristillus series, the entire Lunar Colony pretty much counts as this, especially from the perspective of the Earth government. The colony is composed of miles of tunnels carved out by tunnel-boring machines under the lunar surface of the Aristillus crater, and when the Earth military invades the colony they find it a maze of twists, turns, and angry natives trying to kill them with extremely large guns.
  • The titular "Big Four" in the Hercule Poirot novel The Big Four. It's under a mountain in Italy, where the final confrontation between Hercule and (three of) the Big Four takes place.
  • Willy Wonka's crazy factory in Charlie and the Chocolate Factory is mostly underground. The book contains an explicit explanation of this by Wonka, where he tells everyone that he decided to expand his factory by tunnelling downward and outward so that he could basically expand indefinitely. (Fridge thinking suggests that he wouldn't have to buy any more land or pay any rent to the property owners most of his factory is under, either; this would of course be all kinds of illegal in real life, but Wonka likely doesn't care.)
  • David Wingrove's Chung Kuo has a series of underground bases in the Alps, the only part of Europe that is not occupied by the City or its plantations
  • The government's Daemon task force base is largely underground. The trope is subverted (in a moment that is simultaneously hilarious and horrifying) in that the Daemon's operatives know exactly where the base is — in their Augmented Reality goggles there is a huge neon sign floating above it saying "Super Secret Daemon Task Force Headquarters" — and simply allow it to continue operating because it poses no threat to them.
  • A similar rationale to Wonka's stands for the enormous set of underground tunnels built by the deep-down dwarfs in Ankh-Morpork in Terry Pratchett's Discworld novels. By digging under the city, they can create their own dwarfs-only authentic dwarf mine under the city, unbeholden to city law or city rents. (In regions with larger dwarfish populations, there really is a separate "surface law" and "deep law".) After the events of Thud!, the deep-downers are thoroughly discredited and Lord Vetinari appropriates their delve for the city government, possibly as the basis of a future Ankh-Morpork subway system. Notably, Commander Vimes actually realizes the "dirt has to go somewhere" problem and realizes the extent of the digging when he has his Disorganizer look through the gate reports for an increase in garbage leaving the city.
    • how much actual digging was required is debatable, in that what Ankh-Morpork is built on is largely Ankh-morpork. The current city is just the top level of several layers of older buildings and construction, which over the generations have sunk, buried, or just been built over so many times that it is a whole warren of passages and compartments, with old streets ending up as sewer tunnels, and old shops now serving as the (often unknown) basements or subbasements to current buildings.
  • In Doom: Hell on Earth, the Mormons have built a sprawling bunker complex under Salt Lake City. Lampshaded by Fly when it reminds him of a James Bond movie.
  • The Illuminati's Bavarian headquarters in Duumvirate is one of these. Parts of it are a couple of centuries old.
  • In the Dale Brown novel Fatal Terrain, Taiwan has a secret underground air base.
  • Dénis Lindbohm's Frostens barn (Children of the Frost, given the context of the story) features this trope as the home of the surviving remnants of humanity and their descendants, with them living in an increasingly sprawling set of constructions under the Scandinavian Mountains. In-story, more installations were supposed to be built... but they were either unfinished or sabotaged when World War III came.
  • To a lesser extent, the cloning facility on Dantooine in Galaxy of Fear.
  • Center, The Chessmaster AI of The General series located in a warren of abandoned hi-tech tunnels deep beneath East residence. It is unclear whether this ancient HQ was designed to be underground or has been buried by subsistence over the millennia since the Fall.
  • Harry Potter
    • Hogwarts has three large dungeons, all associated with Slytherin. The most prominent one is the Slytherin Common Room, which is partly located beneath the Great Lake, giving it a greenish hue. The second is the Potions Classroom, rather fitting since the two professors who teach the subject are Slytherins. The third is the Chamber of Secrets, the lair of Salazar Slytherin's basilisk.
    • The Ministry of Magic is completely underground. It can be reached via elevator telephone booth, flushing down magic toilets (no joke), Apparation or Floo powder. Like the Great Hall's sky ceiling, the windows are enchanted to allow daylight to filter in (or hurricanes, when the maintenance staff is angling for a raise).
  • The Hunger Games gives us District 13, which is extraordinarily large.
  • The Lost Redeemer: Whitecliff has many underground tunnels and chambers including a harbor, a library, and a secret tomb.
  • The sapient rats from Mrs. Frisby and the Rats of NIMH built themselves a Mouse World version of this trope under the farm. No actual Applied Phlebotinum is present by human standards, but by the standards of other animals, it's a regular Mad Scientist Laboratory.
  • Mrs. Smith's Spy School For Girls: Double Cross: The Ghost has a base located under an old abandoned plantation in Hawaii. It's built into a network of underground lava tubes.
  • In the Dirk Pitt Adventures, Dirk Pitt has infiltrated his share of these.
  • The Red Tower had three factory floors, but no doors or loading bays; the novelties it produced were distributed through a vast network of subterranean tunnels and minecart rails that permeate the surrounding wasteland. The first destruction of its machinery merely forced its operations deeper below ground, with a second level becoming home to its birthing graves, and an unknown deeper third level whose existence is only rumoured.
  • The Calvarians of The Reynard Cycle build entire cities underground due to the harsh weather of their homeland.
  • Salamandastron for the Long Patrol, and the Kingdom of Malkariss for one set of baddies, in the Redwall books.
  • In Remember To Always Be Bravethere are four of these. Three out of those are scenes of gory battles throughout the course of the book.
  • In the Rivers of London novel The Hanging Tree, Peter notes that, since rich people don't understand why living in a city with millions of other people means you can't have a huge country house, the posh terraces in Kensington tend to have vast basements and cellars containing swimming pools and bowling alleys, which means that a) most rich people are a volcano away from being supervillains and b) watching the uniforms trying to secure the building gives the impression of a Clown-Car Base. (This is Truth in Television, to the extent that some streets in Kensington actually have a serious subsidence problem.)
  • Faery Airbase in Sentou Yousei Yukikaze is a mixed bag, in that much of the base is aboveground, but a significant portion of the facilities and hangars are located underground, such as the Special Air Force's hangar and support facilities. There's even an Underground City where Faery Air Force personnel live.
  • The Observatory in Septimus Heap is heavily hinted at to be this.
  • In Shatter Me Castle creates Omega Point, an underground city where people with gifts gather to plan a rebellion against the oppressive Reestablishment.
  • The Alchemists' Guild in A Song of Ice and Fire has an elaborate underground Guildhall composed of a labyrinth of tunnels, cells, halls, and warehouses filled with highly explosive wildfire. The place is designed to limit the damage should a cache of wildfire combust.
  • Supervillain Doctor Impossible of Soon I Will Be Invincible has a base descending deep into the Earth: when he returns to it after his last defeat, the deeper levels are still intact. Also, his first base was dug down from the basement of an ordinary suburban house.
  • Chrysalis Base from Star Trek: The Eugenics Wars is a giant underground research facility with labs, a nuclear reactor, an underground garden, and even several classrooms. Great lengths have been taken to make it aesthetically pleasing and a nice place to live for the scientists there.
  • In Star Trek: The Genesis Wave, the Lomarians (Plant Aliens responsible for unleashing the titular weapon) have one of these. It's justified in that the ecological devastation on Lomar has forced their people underground.
  • In Kim Newman's short story "Swellhead", the ghostly remains of the Elaborate Underground Base of a supervillain from an Alternate Universe are beginning to seep into our world with disastrous consequences. The difficulties of building such a lair without elaborate funding or anyone knowing about it is lampshaded at one point (and is the clue to its nature).
  • The Thrawn Trilogy has the Mount Tantiss facility on Wayland, a massive complex where The Emperor keeps all the potentially useful bits of tech he's collected.
  • In the Time Scout series, half the action takes place on time terminal 86, in a winding cavernous complex in the heart of a Tibetan mountain in 1912.
  • Whateley Universe: Superhero School Whateley Academy has extensive underground stuff. Powers testing, deviser workshops, arenas, you name it. And that doesn't even cover the highly dangerous sewer system there. Lampshaded by mentions that they now have to be quite careful where and how much they dig, in order to avoid having the above-ground structures fall into a sinkhole.
    • Underground lairs are also popular with supervillains and villainous spy agencies, with a number of them coming up in stories set off-campus. Two different criminal enterprises are shown which specialize in constructing such lairs, and major villains with multiple lairs sometimes lease out bases to less successful villains when not in active use.
  • Tolkien's Legendarium:
    • The Hobbit:
      • The dwarf Kingdom Under-The-Mountain in the Lonely Mountain.
      • The underground-dwelling Wood Elves of Mirkwood.
    • The Lord of the Rings:
      • Khazad-dûm (Moria), the ancient dwarven country under the Misty Mountains. Dwarves in general prefer to live in these sorts of places.
      • The Dead Men of Dunharrow lived in an elaborate system of caves in the mountains (when they were still alive, presumably) and were still there 3,000 years after they'd died.
      • Hobbits, despite their general preference for underground living, don't have these.
    • The Silmarillion:
      • Morgoth had Utumno, which amounted to an underground country, plus Angband (whose excavation produced enough refuse and slag to pile into an enormous mountain). Both were filled with vast mines, dungeons, torture chambers, and other... pleasant things.
      • Elves vastly prefer to live above-ground, but oddly enough a few groups also built/excavated underground fortress-cities.
    • The Children of Húrin:
      • Nargothrond, the underground fortress on the river Narog, destroyed by Glaurung the dragon.
      • Even the Petty-dwarves have a hall under a large hill.
    • Beren and Lúthien features Menegroth, the Thousand Caves, an elaborate elven subterranean city built with Dwarven assistance.
    • The Fall of Gondolin: The titular city hidden is a subversion: a shining city on a hill, but hidden away behind almost impenetrable mountains (possibly a big crater or caldera), so effectively underground as far as concealment and defense are concerned.
  • The Witch of Knightcharm: A Scholomance student named Lauren tells Emily that their evil Wizarding School is a facility in a big underground cave, as per the traditional myth.

    Live-Action TV 
  • On The 100, Mount Weather is an enormous underground bunker, used to house a small (but technologically advanced) community of people who can't survive on the radiation-soaked surface.
  • Agents of S.H.I.E.L.D.:
    • S.H.I.E.L.D. has a number of underground bases and facilities, the main example being the Playground, which acts as their main headquarters from the end of the first season until its destruction midway through the fourth. As Coulson is reconciling with another branch, he uses this as a selling point toward peace.
      Coulson: This way we can have a cool underground base and a boat.
    • In Season 3, HYDRA's main base is a bunker revealed to be built underneath an abandoned oil refinery. Coulson says that they don't even appear to be trying to avoid villain cliches at this point.
    • Season 5 features the Lighthouse, a top-secret bunker created by S.H.I.E.L.D. in the '70s in case of nuclear war. It's so big and so well designed that in a Bad Future where the Earth has shattered, it functions as a perfectly habitable and self-sustaining space station.
    • Season 5 also has General Hale's bunker, which was originally used by HYDRA as a training academy in their heyday.
  • Season 4 of Alias introduced APO, a black-ops branch of the CIA (that most of the CIA doesn't know about) located underneath Los Angeles and accessed by the subway.
  • The Andromeda Strain: Team Wildfire assembles in a high-tech, underground facility to identify and defeat the titular plague before it is too late, and it is located underground in order for them to experiment on it safely without fear of it leaking out.
  • The Avengers (1960s) episode "The Living Dead" had a huge underground city built by the villains for the purpose of raising an army.
  • Xenon Base in Blake's 7 was an Elaborate Underground Base owned by a Villain of the Week. Upon his death, the heroes moved in and made it their base of operations for the remainder of the season. When you are a marginal band of outlaws facing a star-spanning empire, there is significant psychological comfort of being hidden under megatons of rock.
  • Season 4 of Buffy the Vampire Slayer featured a military organization called The Initiative with a massive high-tech base underneath Sunnydale, where they held demons captive and used them for medical experiments. The Master's lair in Season 1 also fits the trope.
    Buffy: You said it was big. You didn't say it was huge.
    Riley: I don't like to brag.
  • Several appear on Chuck. From Season 2 on, Team Bartowski primarily operates out of an underground base hidden beneath the Buy More and Orange Orange. Fulcrum and the Ring both utilized them to house their Intersect research, (conversely, the CIA housed their Intersect in a normal office building) while Volkoff made use of several to house components of the Norseman weapon.
  • Doctor Who:
    • The Silurians are fond of these. As Ultraterrestrials, they spend long periods hibernating in them.
    • "The Sun Makers" was filmed in the real-life deep air raid shelters of London.
    • "Dalek" features the secret bunker of billionaire Henry van Statten, located in Utah. It houses his secret museum of alien artifacts, including one live specimen. Take another look at the title of this episode and make a wild guess what the "Metaltron" is.
    • "The Christmas Invasion" revealed that UNIT had a massive subterranean base underneath the Tower of London, of all places, its excavations and comings and goings seemingly unnoticed by the attraction's thousands of visitors.
    • "The Runaway Bride": The Doctor finds an elaborate ex-Torchwood One research facility beneath the Thames river in London.
  • The Dollhouse underneath Los Angeles is pretty much a self-sustaining spa eight stories down.
  • Basically subverted in the Elementary episode “Ready or Not”; an investigation of ‘the Keep’, an apparent underground facility based in an old Cold War bunker, allegedly intended to protect the elite in the event of a nuclear holocaust, swiftly reveals to Holmes and Watson that it’s all an elaborate scam to get money out of the intended residents. They deduce that the bunker provides the kind of superficial comforts that the target residents would look for, but it lacks more sophisticated details such as appropriate air filtration systems, the walls are damaged behind the immediate coverings, and the cupboards are full of empty boxes to give the impression of medical and food supplies being kept in storage.
  • The Temple of the Cardinal Witches from Emerald City. The visible part looks like a fairly modest chapel, but beneath it, there is a truly massive chamber, hundreds of times larger, where the spells of all the deceased witches are kept in jars. In "No Place Like Home", Dorothy either destroys or damages it heavily with the stone giant's sword in order to stop Glinda and her witches.
  • Sheriff Jack Carter in Eureka lives in an experimental intelligent house that is underground. It doesn't fulfill all of the requirements, but it's underground, it's where he lives, and it's full of exciting gadgets, so it counts.
  • In Helix, isolated research base Arctic Biosystems has several subterranean levels, the depth, and extensiveness of which initially jar the CDC team sent to investigate there.
  • In Hogan's Heroes, the Allied POWs/spies had a network of tunnels under Stalag 13, to which Colonel Klink was consistently oblivious — not the sort of cramped tunnels POWs might dig with spoons, but what you would find in a long-worked industrial mine. How the tunnels had been dug undetected was never explained. Lampshaded in one episode in which the grounds have even more snow than usual, and the POWs have built a snowman. At one point, Col. Hogan indicates a particular patch of dirt and claims that it is "the only spot in camp that doesn't have a tunnel under it."
  • JAG: In "Sightings", the abandoned military airfield was built with underground aircraft shelters, being used by drug runners to conceal their operation.
  • Most of the Dharma stations on Lost are partially or completely underground, and are of varying complexity. The Pearl and the Orchid are entirely underground. The Orchid is quite elaborate and gives way to an even deeper cave containing the wheel which moves the island.
  • Madan Senki Ryukendo has such a base hidden beneath a police station, accessed by praying to the elevator (really). It also serves as a Haunted Headquarters.
  • M.I. 9 has an Elaborate Underground Base concealed beneath St Hope's School in M.I. High. Given it houses only three operatives and their handler, it does seem somewhat like overkill.
  • The titular team in Mutant X has a fairly spacious and comfy facility inside a mountain with a hologram covering the entrance. It looks more like a loft than a secret base.
  • Deep 13 from Mystery Science Theater 3000, supposedly. It's all in the name.
  • Neil Gaiman's Neverwhere features an entire sub-culture beneath London. There were also undergrounds beneath every major city on Earth, each distinctively dangerous. At least according to Huntress.
  • Odd Squad: Most Odd Squad precincts' Headquarters, including Precinct 13579's, are situated deep underground. "Fistful of Fruit Juice" reveals that the idea to have underground Headquarters was the work of Big Red, a citizen of Oprah's hometown who wanted to thank her for retrieving his stolen mailboxes and decided to dig the tube system as a result. The Headquarters vary by precinct, but most of them have laboratories for the Scientists, North and South Control Rooms for the Security agents, and numerous rooms that range from practical (the Bedroom) to downright absurd (the Potato Room). The only aversion is the Arctic Odd Squad precinct's Headquarters, which is aboveground and is more low-budget than the Headquarters commonly seen, with a smaller lab area (which is useless considering the precinct doesn't use gadgets), a couple of tables for a makeshift Breakroom, and a small pool filled with plastic balls.
  • The Peripheral (2022): The Research Institute. It goes down at least 95 storeys, and contains an aquarium large enough to hold whales, hydroponics farms, factories, and Lord knows what else. The use of Assembler Nanomachines probably serves to Handwave the financial and structural constraints that a facility of this magnitude would face in Real Life.
  • Person of Interest: From the fourth season onwards, Team Machine uses an abandoned subway station as headquarters.
  • Power Rangers uses this quite often. Some seasons, such as the original, simply imply it, while others are more blatant about it. The fifteenth season, Operation Overdrive, commonly does a cutaway to the base by showing the aboveground mansion and then dropping the camera via CGI through several layers of planetary crust. For added hijinks, the Rangers in this season are implied to be sliding down kilometer-length fireman poles to reach said base. And on top of that, they have three Humongous Mecha and a Cool Ship hidden inside.
  • The second season of Space: 1999 saw the command team move from the above-ground "Main Mission" set to a "Command Center" located deep underground.
  • Stargate-verse:
    • In Stargate SG-1, Stargate Command functions as an Elaborate Underground Base that includes a functioning interplanetary wormhole (see "Real Life" example, below). In later seasons, the "Alpha Site", "Beta Site" and "Gamma Site" are all built as copies of the SGC on other planets.
    • When the Eurondans decided to exterminate their enemies via Atmosphere Abuse, they built a massive underground base that could house them for decades.
    • The Genii of Stargate Atlantis act like Space Amish while actually living in these. Their true nature gradually becomes one of the worst-kept secrets in the galaxy.
  • Stargirl (2020): The Injustice Society operates out of a bunker secreted in the heart of a Tunnel Network running underneath Blue Valley, Nebraska. At the very least, it contains a central meeting room, Dragon King's laboratory, and a staging ground for building Project New America. It's revealed later that it was built by the founders of the town long before the Injustice Society ever arrived; the Injustice Society specifically chose the town because they learned of the tunnels and figured it would make a good hiding place.
  • Stranger Things: In Season 3, the Soviets infiltrate Hawkins by means of the Starcourt Mall, beneath which is revealed to be a massive laboratory complex wherein they're trying to open a Gate to the Upside Down.
  • In the ninth episode of Strike Back: Project Dawn, Scott and Stonebridge find their way into a system of Cold War-era underground bunkers, which the Big Bad Latif was using as his base. Among the amenities are various storage, manufacturing and testing facilities for Weapons of Mass Destruction, which Latif had used in the development of his VX distribution system. A number of corridors are shown that could fit a tractor-trailer, and satellite scans indicate that the system is about 50 kilometers across and forms a five-point star.
  • From Season 8 of Supernatural onwards, Sam and Dean have the Men of Letters' bunker.
  • Super Sentai used this in multiple series. Zyuranger, Ohranger and Go-Busters are prominent examples. The Go-Busters base has tunnels that extend to various areas of the city, similar to an anthill, and the Zyurangers' base (located beneath an apartment building) has portals to other dimensions.
  • The 60s series The Time Tunnel featured a colossal underground base that housed the titular Time Travel device.
  • Torchwood Three in Torchwood is hidden under Roald Dahl Plass, Cardiff. This is in stark contrast to Torchwood One's tower in Doctor Who, which is Canary Wharf. The Torchwood Three base was a deviation from the classic luxurious underground base — aside from the central hub, it was a rat-nest of cramped rooms and converted tunnels that have been repurposed and rebuilt over decades, it was dim and dingy, and water was always leaking in from Tiger Bay. The trope is Lampshaded in Children of Earth.
    Rupesh: What's in there?
    Gwen: Big... science fiction superbase. Honestly!
  • SHADO Headquarters in UFO (1970) is located beneath a film studio. Think about it...
  • The Ultra Garrison base in Ultraseven is located 18 stories down. This is Played for Drama in "Challenge at -140 Degrees" when a power outage and a Cold Snap caused by aliens threatened to kill a crew of 300 people inside while The Hero is stranded outside, unable to transform.


  • Malevolent features a few, including an entire underground city beneath a hotel.

    Puppet Shows 
  • Gerry Anderson seems quite fond of this one.
    • In Joe 90 the BIG RAT was located in a secret underground facility beneath Professor McClaine's house.
    • In Stingray (1964), during alerts the entire city of Marineville can descend into a secure underground facility on hydraulic jacks. (Just in case anyone thought Neon Genesis Evangelion did that first...)
    • Thunderbirds of course had the Thunderbird hangars beneath Tracy Island.
  • British puppet character Roland Rat was originally supposed to live in the sewers beneath King's Cross railway station. In Roland Rat The Series this suddenly became "the Ratcave"; an Elaborate Underground Base containing living quarters, a talk show studio, and a reception area, and accessed from a hidden lift in a workman's shelter outside the station.

    Tabletop Games 
  • Despite the name, virtually none of the "dungeons" in any Dungeons & Dragons campaign are prisons. They're either natural caverns full of unintelligent monsters (rare), tombs full of undead (uncommon), or this trope for the Villain of the Week (extremely common).

    Taking this to its logical extreme is Malsheem, fortress of Asmodeus, god of sin and tyranny and lord of devils. As the fourth edition has transformed the Nine Hells into a planet, Asmodeus' fortress is comprised of the entire core of that planet.
    • In the 5th ed. adventure book Waterdeep: Dungeon of the Mad Mage, the titular mad mage Halaster Blackcloak has his home Undermountain built into the fallen underground dwarf kingdom of Melairbode. This underground base is so extensive that it has several different realms which are only accessible by special dimensional gates as well as a Nigh-Invulnerable guest castle made of stone, glass, crystal, and adamantine.
  • The Jadeborn in Exalted, being the game's rough equivalent of dwarves/elves/gnomes, built underground cities, nations, military bases, factories, incomprehensible giant artifacts, and everything else an entire civilization of genius-craftsmen-artificers-inventors-engineers could produce over millennia of flourishing. In the Second Age their world-spanning underground empire has long since crumbled, but their remaining cities are still vast and elaborate and thoroughly underground.
  • Alpha Complex from Paranoia is usually an elaborate underground warren with all the super-science facilities you could ever need. note 
  • Classic Traveller Adventure 3 Twilight's Peak. A large Ancient base on the planet Fulacin was hidden underground. It was captured by the Zhodani, who secretly controlled Fulacin, and used by them during the Fifth Frontier War.
  • The entire raison d'etre of House Telamones, Nosferatu bloodline from Vampire: The Requiem. They build elaborate underground bases to suit the tastes of their undead betters, but woe to the Would-Be Vampire Overlord who accepts the bid from a competing firm... it's mentioned in the text that House Telamones has blown up an entire city block of Seattle rather than lose a bid.
  • The dwarves of Warhammer live in huge underground cities, following the example set by J. R. R. Tolkien. And the Skaven live below those in big cities and tunnels that span every continent.
  • Warhammer 40,000 gives us the planet of Calth in the Ultramar sector, where there are bases, cities, and agricultural communities built up in the planet's massive cavern system because the sun is deadly. Necron tomb complexes also qualify.


    Theme Parks 

    Video Games  
  • The Alpha Protocol base in, well, Alpha Protocol is a large underground complex apparently located somewhere in the American northwest. Reaching it is pretty difficult; agents are sedated into unconsciousness and transported to the location, via aircraft and boat in order to keep the base's location secret. At least until the endgame, where Mike arranges for his allies to track him while he's being sedated and ruin everyone's whole week with a surprise assault.
  • The moonbase setting of BioForge, complete with hangar bay, cryogenics lab, prison, defense tower, and medical experimentation lab.
  • BioShock takes place in a underwater city/base named Rapture, where Applied Phlebotinum is developed, refined, and horribly goes wrong — the player's stated goal is to get out alive.
  • The whole of Breath of Fire: Dragon Quarter takes place in a geofront-like super cave.
  • Carmen Sandiego: Math Detective: The game opens with you infiltrating one used by VILE.
    Chase Devineaux: [whistles] Some new headquarters! Carmen's really outdone herself.
  • City of Heroes:
    • The game features this to an almost ridiculous extent. The Cobra-wannabe Council (formerly the Fifth Column) generally base themselves in converted caves, as do the Rikti, and even the evil cultist Circle of Thorns have their ancient underground city. The Faultline zone (former Scrappy Level Rescued from the Scrappy Heap) is said to be filled with former superhero bases that were abandoned in the earthquake that gave the zone its name, and people are trying to dig them up...
    • Not to mention the Shadow Shard — an alternate dimension seemingly comprised entirely of floating islands in the sky, with caves and bases dug into them anyway. If the game world had a consistent geometry, it'd likely resemble a very big ant hill with more empty space than rock.
  • Underground Laborotories and Subterranian Complexes in Clicking Bad.
  • Colossal Cave, including the maze of twisty little passages, all alike.
  • Command & Conquer:
    • Nearly all of the Brotherhood of Nod's military facilities have some kind of extensive underground component. For example, the Hand of Nod has a massive training and fitness area, as well as a mock-up forest environment for combat practice, and an interrogation cellar.
    • Expanding on that, in Command & Conquer: Red Alert, there were the beautiful and famed internal missions. With computer consoles that actually did things.
    • The Twisted Insurrection mod for Command & Conquer: Tiberian Sun also features several missions taking place in underground facilities.
  • The Descent lives for this trope. Granted, a lot of them are mines, but there are a bunch of military, scientific, and testing facilities as well. Of particular note is the final level of Descent 3, Dravis' Stronghold.
  • Deus Ex:
    • The first game concludes in Bob Page's base beneath Area 51. On the good side, Tracer Tong has a sophisticated laboratory several floors beneath his Triad's compound.
    • UNATCO Headquarters is itself underground, with an MJ-12 base beneath it. Yes, the game has an example of an underground base beneath another underground base.
    • UNATCO Headquarters makes a return appearance in Deus Ex: Invisible War.
    • Deus Ex: Human Revolution features several underground bases — a FEMA facility, the Harvesters' hideout, and Panchaea to name a few.
    • Deus Ex: Mankind Divided continues the trend, with Task Force 29's Prague headquarters hidden in a cavern beneath a front company's office, accessible only by a long elevator ride. Downplayed by the GARM facility, which is mostly hidden inside a mountain in the Swiss Alps, but not completely underground.
  • Dwarf Fortress: Although you don't technically have to do this — one of the DF Wiki's "optional goals" is to create a fortress that is based entirely around surface structures.
  • The Elder Scrolls
    • In the backstory, the Dwemer combined this with Advanced Ancient Acropolis, building their complex and technologically advanced cities into the ground. Some, such as their strongholds around Red Mountain in Vvardenfell and Blackreach beneath Skyrim, are absolutely massive and extremely elaborate. Justified as they were known to use geothermal energy to power their cities, which also justifies their preserved states and Eternal Engines that are still running when visited in the games even though the Dwemer have been gone for thousands of years. (Along with their habit of bending the laws of physics and nature.)
    • Morrowind has dozens of caves and grottos, some of which get quite elaborate, and are usually home to smugglers, bandits, or worse. Dunmer Ancestral Tombs and the aforementioned Dwemer ruins are also typically built into the ground.
    • In Oblivion, you can get one for yourself via the Thieves Den DLC. It is pirate-themed and, once taken over, allows you to recruit pirates to give services (like skill-training and selling stuff like lockpicks) and go out stealing for your benefit.
    • Skyrim continues the tradition of having countless smuggler/bandit/necromancer/etc. hideouts in the form of underground caves and ruins. Once again, many get extremely advanced. This is especially true of the old Nordic burials, which are complete underground ruins that can reach the size of full-blown cities. Additionally, the Dwemer ruins return in full force with plenty of great examples, many of which have been taken over by their former Slave Race, the Falmer. The Falmer are also shown to be capable of constructing elaborate networks of suspended bridges and platforms.
  • Evil Genius is entirely about building one of these, the larger and more full of traps the better! Now you just have to watch out for those pesky law enforcement agents sneaking in to make trouble...
  • From the Fallout games, the various Vaults.
    • Fallout had the Glow, the Mariposa Military Base, and the Brotherhood's Lost Hills HQ.
    • Fallout 2 had the Sierra Army Depot and the Hubologist base. The Brotherhood bunkers in the Den, NCR, and San Francisco might also count.
    • Fallout 3 had Raven Rock and the Rockland comm. facility.
    • Fallout 4 has The Institute, which is so elaborate that the only way to access it is through teleportation — at least until the end where you access it through other means, such as a hidden tunnel or by blasting through the surface with a Humongous Mecha.
    • Fallout Tactics: Brotherhood of Steel had the Brotherhood bunkers and Vault 0 which was simply the Cheyenne Mountain Complex converted into an even larger facility.
    • Fallout: New Vegas has several: the Brotherhood, as usual, lives in an underground bunker, the Enclave remnants keep their Powered Armor and vertibird in one, and Mr. House has a Mecha-Mooks factory built under Fortification Hill. The Big MT Research and Development Center from Old World Blues used to be one (back when it was, you know, a mountain), but then the Mad Scientists there blew the top off of it.
  • Final Fantasy V had the Catapult, an underground/underwater base of Lost Technology. Among other things, it features an airship docking bay, a teleporter, and a ship-sized elevator to the sea surface. And the icing on the cake? It's yours now.
  • In Fire Emblem: Three Houses, those who slither in the dark/the Agarthans have one of these, which explains how they've avoided detection for so long.
  • F.E.A.R.:
    • Armacham Technology Corporation established the main facility for the Origin Project in an old military-industrial complex and built the entire facility deep underground. Emphasis placed on the past tense, what with the explosive ending of the first game.
    • Project Origin takes it even further. The Auburn Memorial Hospital is a full-sized building constructed underground inside another Elaborate Underground Base. Wade Elementary has another Elaborate Underground Base beneath it. And that's before you get to the giant tram tunnels running through titanic chambers that include a Replica storage facility and massive maintenance area. Pretty much the entirety of Fairport is riddled with Armacham secret bases. One wonders how nobody found out about it or that all the excavations didn't fatally weaken the ground.
  • In Gabriel Knight: Sins of the Fathers, the voodoo cartel has a temple doubling as their headquarters under Jackson Square. It's hinted to have been built in the 19th century when the cathedral had to be rebuilt from scratch. Still, hiding a secret side project that big would take a lot from Marie Laveau's followers and clients.
  • Gears of War features the hollow, which is home to the entire Locust civilization. It runs all throughout the planet and there are areas inside of it big enough to have skyscrapers and air patrols.
  • In Grand Theft Auto: San Andreas, Carl must infiltrate one of these under a base called Area 69. Yes, it's inspired by Area 51 (see below).
  • Half-Life:
    • The Black Mesa Research Facility is one of the biggest and most elaborate underground bases ever shown in detail. It is a repurposed top-secret rocket research facility from the Cold War that has been upgraded to house a massive Teleportation and Inter-Dimensional Travel research project. It has its own hydroelectric power plant, nuclear waste disposal facilities, and a dormitory complex big enough to allow at least the top researchers to have their families living with them, which also requires multiple security checks for all personnel when moving between sectors. Which is usually done by using the local monorail tram network. Some of the largest and longest levels of the game and its add-ons take place in the Freight Yard, which consists of a large number of warehouses and its own container terminal to unload the 40-feet-containers that arrive by train. The fact that outdoor environments look just awful in the old Quake-derived engine may have had more than a bit to do with the base ending up mostly underground. The few outdoor levels that exist consist entirely of brown rocks and concrete walls.
    • In the end it takes an underground nuclear bomb to eliminate any remaining witnesses and all alien forces still inside the facility. Though that event might be non-canon and is neither mentioned by the games from the main series developers nor does it fit with the details revealed in later games.
    • It also is probably no coincidence that the Black Mesa Research Facility is located in New Mexico, putting it in the general region of the real world Los Alamos National Laboratory (atomic bomb), Edwards Air Force Base, Arizona or "Area 51" (experimental jet-aircraft), and Black Mesa Test Range, Utah (ballistic missiles).
  • Halo:
    • Halo 3 — the second level takes place in Crow's Nest, an "old 20th century" military base inside Mount Kilimanjaro, which has been re-activated after the Covenant took over Earth. This base comes fully equipped with a hangar bay, hidden landing pads, big imposing steel doors, and a war room, complete with big screens and Bridge Bunnies.
    • Halo: Reach: Sword Base has a massive research facility hidden in the ice shelf deep below the base.
    • The world of Reach also has CASTLE Base, an ONI facility hidden two kilometers directly underneath Menachite Mountain.
  • In Hitman (2016), Silvio Caruso has an entire laboratory filled with scientists and guards in a cave underneath his estate. It's justified as being built by the company he's working for since he's an agoraphobe who hates traveling.
  • Kuri Kinton: The game is set inside a huge underground base full of enemies and bosses. The Player Character goes there to rescue a senior policeman and his daughter.
  • Fort Schmerzen in Medal of Honor and Allied Assault.
  • In the first Mega Man Zero game, the La Résistance's base is located underneath an abandoned city. While the "base" itself is run-down, there is still some machinery functioning there, like an elevator and a teleporter. The base, after numerous attacks, was completely abandoned by the group in favor of a more elaborate, newer base (although it's not underground anymore).
  • Vanishing Gungaroo's stage from Mega Man X7.
  • Metal Gear:
    • In Metal Gear and Metal Gear Solid, the titular Humongous Mecha is hidden in one of these.
    • Metal Gear 2 has a variation: Although Metal Gear D is fought in the third (sixth?) basement floor of the main building of Zanzibar Land's detention center, it is not specified if it was actually the main hangar for Metal Gear D.
    • In Metal Gear Solid: Portable Ops, there are three elaborate underground bases: One is the Nuclear Storage Facility (which is the deepest mapped area of the game), another is the Silo Complex (which is pretty deep underground, although the mapped areas themselves are actually shallower than the Nuclear Storage Facility), and it was originally intended in-game to have more than one missile silo. The last one isn't actually visited by the Player: It is the underground bunker underneath Langley that the CIA director attempted to retreat under with the impending nuclear strike against America with his half of the Legacy, and where Ocelot essentially murdered him and made it look like he committed suicide.
    • In Metal Gear Solid: Peace Walker, both the heroes and the villains have elaborate bases: The Peace Sentinels had an AI Weapon assembly plant situated within a pumped storage hydroelectric power plant within Irazu's crater, an AI programming lab constructed either within an unknown ruin or an AI lab disguised as a ruin (Paz's description of the plant makes the ruin's exact origin a bit ambiguous), and an AI Weapons forwarding/Peace Walker construction base built within a gold quarry. In addition, the FSLN / KGB's drug facilities were also disguised as Banana and Coffee processing factories, and the Militaires Sans Frontieres also utilized an elaborate base in the form of an off-shore OTEC research facility.
  • Metro 2033 features the entire subway system of Moscow, which is home to the remnants of civilization. It also features huge military installations even below that.
  • Most Space Pirate bases in Metroid games tend to be these. Probably because both their homeworld and their main base at Zebes are plagued by near-constant acid rain.
  • The Ancients in (old verse) Might and Magic seems to have been fond of placing large facilities underground. The inhabitants of Deyja went one step beyond and built themselves an Elaborate Underground City.
  • You can build these in Minecraft. The biggest typically have some or all of the following: entrance, underground railway tunnel, security system, security doors, central hub room, end portal, nether portal, brewery, massive automatic crop farms, automatic animal farms, enchanting room, super-smelter, armory, cinema, bedroom, garage, slime-block tank, missile silo.
  • The Russian missile base in the last act of Modern Warfare, which is also Ye Olde Nuclear Silo.
  • Mother:
  • The No One Lives Forever series had a couple. The first game had one in the US Pacific Northwest and an underground rocket launch facility somewhere in the South Pacific. The second had an underwater base you had to infiltrate.
  • One Dog Story is set in a huge underground base. The dog needs to explore it to regain his memories.
  • The entirety of OverBlood takes place in one.
  • Naoto's dungeon in Persona 4 is one of these.
  • Pokémon:
    • Pokémon Red and Blue and Gold and Silver and their remakes have the Team Rocket bases, which is actually pretty elaborate considering they tend to build them under game corners and converted ninja bases.
    • The spinOff games Pokémon Colosseum and Pokémon XD: Gale of Darkness had the Cipher Lab, which was rather complex. The only thing is, there was one floor on the upper level that was actually important for getting through the base (the button needed to unlock the door was there), so it can't be considered a true base.
    • As well as the first Pokémon Ranger, where the Go-Rock Squad's base is underground in a mountain.
    • It continues in Pokémon Ruby and Sapphire and Emerald, with the Team Aqua and Magma bases; in the former two, the antagonistic team's base is hidden in a seaside cave near Lilycove City, while in Emerald, Team Aqua takes the cave and Team Magma has a base inside the Hoenn region's active volcano, Mt. Chimney.
    • In Pokémon Black and White, Team Plasma built N's Castle underneath the Pokémon League. (It still exists in the sequels, but it isn't a proper base anymore and has long since been abandoned.)
    • Pokémon X and Y has one Team Flare base under Lysandre Cafe and one underground at Geosenge Town.
  • The Aperture Science Enrichment Center in Portal is located, per the supplementary material, in an abandoned salt mine in Cleveland, Ohio. Portal 2 bizarrely retcons this to be in Upper Michigan, but also takes the player on an exploration of the true vastness of the place. Elaborate barely even begins to describe it: some parts of the game take place as much as four kilometers underground, and the player is treated to vistas of immense facilities stretching as far as the eye can see, constructed over a period of at least fifty years.
  • Rayman 3: Hoodlum Havoc: The Hoodlum Headquarters area as well as the majority of the Desert of the Knaaren level, the latter potentially justified by the fact it's a natural cave system. Doesn't explain why it also has a mini Temple of Doom inside it too though.
  • In Resident Evil, seemingly every building in Raccoon City, or in the forests surrounding it, has at least one well-hidden elevator leading into one of the multiple underground Umbrella Corporation labs (which makes sense when you consider that Umbrella essentially owns and runs the city).
  • The British army in Resistance: Fall of Man has two underground bases from which they were staging their attacks on the Chimera. Extra content reveals that they had a third underground base, but it was flooded by the Chimera before the start of the game.
  • In Rimworld, for the longest time the most dominant base-building strategy was to dig one into the side of a mountain. Not the most flexible or elegant approach by any means, but by far the least resource intensive and the easiest to defend. Insect hive infestations and Cabin Fever were introduced in a later version to try to remedy things and make mountain bases less of a sure bet.
  • Saints Row 2 features a base called The Pyramid hidden under a mountain. Amazingly, the company that built it was a clothing company in the first game set five years earlier. The Saints themselves have their headquarters in an abandoned hotel that collapsed below street level after an earthquake many years previously. Eventually, it is renovated into a sumptuous, neon-lit, subterranean nightclub called "Purgatory."
  • The Secret World:
    • The Illuminati operate from one of these in Brooklyn: known as the Labyrinth, it can only be entered via hidden entrances concealed in the sewers and cellars of the area and is heavily guarded against intrusions by non-Illuminati personnel. Among other things, it features testing chambers, a Mad Scientist Laboratory, a vast server farm, a colossal pyramid-shaped concourse, and a lot of areas that are officially off-limits to the player — unless you've made a huge mistake.
    • The Morninglight have a "clubhouse" hidden under the Tokyo docks, intended to lure in the best and the brightest of potential recruits. Initially, it appears to only consist of an underground social club, with a bar, video arcade, swimming pool, shooting range, and gym... but for those who've been earmarked for greater things by the Morninglight higher-ups, a chip-activated door reveals the complex also features a massive stadium-sized temple, complete with marble floors, sculpted columns, a colossal domed ceiling, and artworks. Plus, it's also got a cafeteria and offices for the Morninglight missionaries. Of course, by the time you get there, the place has been overtaken by the Filth, and the members have either been infected, killed, or forced to flee.
    • As if it wasn't enough to own an Evil Tower of Ominousness big enough to give the Burj Khalifa an inferiority complex, the Orochi Group have a gargantuan factory hidden beneath their Tower headquarters. Known only as the Manufactory, this area — visited only as a dungeon mission — appears to be the size of a small city, and can easily churn out enough drones, tanks, and Humongous Mecha to clog the streets of Tokyo if need be.
  • Shadow Complex is a Metroidvania game that takes place in one gigantic base.
  • In Sid Meier's Alpha Centauri, the Human Hive faction's bases (equivalent to cities in Civilization) are stated in the fluff to be of the underground kind.
  • Skies of Arcadia has elaborate underground bases for both the heroes and the villains.
  • The majority of Still Life 2 is set in an unassuming house in the woods. The house is substantially larger than it appears due to the expanded atomic shelter underneath.
  • Team Fortress 2 has many maps with partial subterranean base setups (most notably, the basements of 2Fort) and the occasional map which takes place entirely underground, such as Junction and Nucleus (despite the latter's open-air midpoint, implied to be the mouth of a dormant volcano).
  • In Thief II: The Metal Age, the Cetus Project is run from Markham's Isle, a former pirate base taken over by the Mechanists. As you learn when you go there, the administration of the project is a bit complicated, but Markham's Isle certainly fits the Island Base and Elaborate Underground Base tropes.
  • The Turing Test: Most of the game takes place in an underground complex located below the icy surface of Europa.
  • In Wasteland, as well as Wasteland 2, numerous pre-apocalyptic military bases and research complexes can be explored. Some of them were adapted to fit their current users' needs, others are abandoned or still serving their intended purpose, crawling with formidable enemies.
  • In WinBack, the GULF control center is hidden beneath a factory and office building.
  • The Witness: The high-tech complex inside the mountain.
  • World of Warcraft:
    • The Dark Iron Dwarves have their own underground base in Blackrock Mountain. Technically so do the Dark Horde and Nefarian, since their towering base is built inside a volcano's cone.
    • The Defias Brotherhood has extensive Deadmines, a combination mining facility, a smelter, a sawmill, and wet dock.
    • The Scholomance is a large school dedicated to dark magic carved out of the crypts of a castle. The Undercity is much the same, only it was built under an entire city.
    • The entire kingdom of the Nerubians was built underground, as is much of the temple to C'thun.
    • After taking the step from "overzealous faction leader" to "raving madman", Garrosh Hellscream commissioned a massive underground fortress, complete with barracks, laboratory, factory, beast pens, treasure vault, and ginormous throne room, built underneath the orcish capital of Orgrimmar. Only one-quarter of the Siege of Orgrimmar raid actually takes place in the aboveground portion of the eponymous city (although some of it is in Pandaria); the bulk of it takes place in Garrosh's bunker.
  • X-COM:
    • All of the X-Com bases (situated and built, room by room, by the player) were only accessible through the main elevator and the vehicle hangars, which affected gameplay if the aliens located said bases and attacked them with a relatively manageable number of alien foot-soldiers.
    • Same goes for Alien Bases, including the main base at Cydonia. Crosses over with Underwater Base in the case of the Colonies and Artifact Sites from Terror From the Deep, which are underground installations built on the ocean floor.
    • The Firaxis remake enhances base-building by allowing you to determine where to dig, and which facilities to place on which level (the original only had one level). It's all the more important here because you're limited to one base, as opposed to the original, where you could have a base on each continent if you wished.
    • The fan mod The XCOM Files has the same underground and underwater bases as UFO Defense and Terror From the Deep, but adds more. Many of new enemies have similar bases, which serve as the final dungeons for their respective arcs. This includes Black Lotus, Red Dawn, post-cult Dagon, Syndicate. Undead and Shogg cave dwellings also qualify. Ditto less elaborate Cyberweb sewer hideouts.
  • The Zork games take this to an extreme, what with most of the games taking place mostly in the Great Underground Empire.
  • Grim Dawn has Warden Krieg's ridiculously large basement that stretches for hundreds of meters. It spawns two levels with a cellar, tunnels, labs, storerooms, jail cells, and living quarters just to name a few. It also has some giant spiders and various beasts that are hostile to the Aetherials and you.

    Visual Novels 

  • Everyday Heroes:
  • In El Goonish Shive, The Nest is the underground remains of the lab where Grace and her "brothers" were created which served as a base for Damien.
  • The military base where the Chio was created in Follower is one of these. Aside from the hangars, most of the base appears to be underground.
  • In Narbonic, Narbonics Labs moved to an underground lair early in the strip's run. Later subverted when Madblood brags to Helen about his underground lair; when she and Mell come to visit, they find him living in his mother's basement.
  • The main characters of The Pocalypse have a base placed under a supermarket in a city.
  • Seems to be the basic design for all Orsintos laboratories in Sluggy Freelance. Surprisingly, there's been nothing so far to suggest that Hereti-Corp has one of these. As it turns out, Dr. Steve's Baselab was designed to burrow underground.
  • In S.S.D.D. Cook has one that was originally a partially completed nuclear storage dump under his corporate headquarters, which he uses for R&D clean rooms, officially. In reality he and the other time travelers trying to prevent the coming Anarchist revolution hide all their future stuff down there. Tessa suspects he might be turning into a supervillain and uses the underground as evidence.
  • Times Like This: It may technically be an Elaborate Underground Base since it's run by a multination secret-service consortium, but Paratopia is actually an underground Club Med-type getaway roughly the size of Delaware.

    Web Original 
  • The eponymous AJCO has never been anything but one of these, even when it was manifested as Pi-TEC in an alternate reality. This is most likely because its CEO grew up in similar facilities during a nuclear war — though its ability to completely confuse and bewilder visitors might be another possible reason.
  • Pelvanida from Darwin's Soldiers is an underground military research base. It is not really "hidden" per se, though, as quite a bit of above-ground infrastructure is present.
  • Random Assault: The Random Assault headquarters, which is an underground skyscraper mansion consisting of many rooms made from all sorts of things, even garbage. The facade above ground is an old, abandoned Circuit City building with the RA logo on the side, as Circuit City buildings are red cubes, very much like the show's logo. Often, guests will be brought to the mansion with a bag over their head so they can't find their way back. The hosts don't live there, either. They use a series of rifts to travel to the mansion from their respective living places around the world.
  • SCP Foundation has a number of underground sites that contain artifacts, creatures, and locations that could burn/rewrite/exterminate the whole world and to an extent the universe if they were to be left unregulated. There is no known exact number of how many underground sites the Foundation has, but these sites could be located in a place where there is a high population density, simply masquerading as an ordinary business, or just located in a simple, well-known army base.

    Western Animation 
  • Gummi Glen in Adventures of the Gummi Bears. This version distinguishes itself by its surprisingly realistic take on an underground structure of such extraordinary complexity in medieval times. Namely, the Glen requires a sophisticated infrastructure like a mechanical ventilation system to maintain air quality while the Gummis have a variety of maintenance concerns like water levels, plant growth, and erosion of the surrounding ground.
  • Avatar: The Last Airbender. The Dai Li had an underground base under a lake.
  • In a series full of Supervillain Lairs to begin with, in the Birdman (1967) episode ("Number One") that brought them into the open and really defined them as a threat, F.E.A.R. turned out to have one of these. One also appeared in the episode "The Quake Threat" (belonging to Dr. Kiroff).
  • The Bots Master: Being a Hero with Bad Publicity wanted as a terrorist, ZZ has to conceal his high-tech house in the underground bomb shelter his grandfather built, along with other efforts to prevent being located by the authorities.
  • In the Chip 'n Dale: Rescue Rangers pilot, Aldrin Klordane had turned a cave conveniently placed underneath the Federal Gold Reserve into his own Elaborate Underground Base which not only has a diagonal monorail but even a real railroad connection.
  • The base Hacker dug out for himself in an episode of Cyberchase. He abandoned it by the next episode, though.
  • Dangermouse lived in an underground base in a postbox on Baker Street in London, the same road as Sherlock Holmes.
  • Vlad built himself one in Danny Phantom by the beginning of Season 3. Through an alternate universe, the underground base was a Foreshadowing element in a previous episode. Too bad he didn't find the time to put it to good use.
  • Dexter's Laboratory, though how underground the lab is isn't really gone into, mostly due to physical impossibility.
  • Don't forget about the Labyrinth in Gargoyles.
  • Invader Zim operates out of a massive network of chamber pods and tunnels buried beneath his house. Among other things, he has a hangar bay for his spaceship, several labs, and an observatory.
  • Jackie Chan Adventures had the underground base of Section 13 in San Francisco. Said organization was where the main characters would live along with being the location of whatever MacGuffins were being collected that season. Could be reached via a phone booth elevator or "the stairs".
  • Jonny Quest TOS.
    • "The Dreadful Doll" has arms and a submarine base being built under the surface of the island.
    • "Pirates From Below" has a base in an underwater cave system equipped with submarines and hovercraft.
    • "The Fraudulent Volcano". A large base was built under/in the title volcano.
  • Global Justice headquarters, and several of Drakken's lairs, in Kim Possible, which also has a twist on the trope: Frugal Lucre's lair in his mom's basement. Also, a few of the locations where Drakken raids are themselves underground bases. Case in point, the episode where he steals some Hypno Trinkets had him raiding a base in the Cold Opening that was built underneath a desert, and a conspicuous cactus acted as a card key scanning device to grant entry.
  • Perry The Platypus has one underneath Phineas and Ferb's house, and the rest of the OWCA base seems to run beneath all of the Tri-State areas. All of it.
  • Hedgequarters from The Mysteries of Alfred Hedgehog is a benign junior version of this trope.
  • The Road Rovers had an Elaborate Underground Base. It was strongly implied in at least one episode that it was the remains of a lab in Socorro, NM, that the Rovers' mentor ran.
  • In The Simpsons, a wealthy businessman and supervillain Hank Scorpio has an underground base with some sort of nuclear-powered ray gun in it, plus a laser for cutting spies in half. It also has a snack vending machine with a touchy dollar bill acceptor.
  • Star Wars: The Clone Wars: The rebels on Ryloth have a nice underground hideout, with the entrance in a crashed Separatist landing craft.
  • Super Friends: In the 1973-74 episode "The Fantastic Frerps", King Plasto has one as his headquarters, including a storage room for his Frerp eggs and a Frerps Arena for creating the eggs.
  • The SWAT Kats have a base hidden beneath the Cool Garage where they live and work.
  • The Teenage Mutant Ninja Turtles live in a hideout within the sewers of New York City.
  • In Teen Titans (2003), multiple villains have one of these over the course of the series, from Slade (at least twice), the HIVE Academy run by Brother Blood, and the final base of the Brotherhood of Evil.
  • The Tracy Island of Thunderbirds could well be the Trope Codifier.

    Real Life 
  • Underground command-and-control centers started getting popular sometime after World War I, and much more so after nuclear weapons and ICBMs. Greenbrier Resort was the site of a US Congressional command center for 30 years, until a Washington Post reporter exposed its existence in 1992. The Cheyenne Mountain Complex in Colorado is quite famous as the "brain" of NORAD (NORth-american Air Defense), SAC (Strategic Air Command, bombers and land-based ICBMs) and the US Space Command (more to do with satellites, though). The latter two are now defunct, absorbed into other organizations. NORAD is now based at Peterson Air Force Base (a conventional above-ground air force base nearby) but keeps Cheyenne Mountain on warm standby.
    • The famous Situation Room (yes, it really does exist) underneath the West Wing of the White House. Yes, this is where the President and his cabinet meet to make life-or-death decisions. No, it is not full of beeping computers.
    • Russia, ex-Soviet Union, undoubtedly has its own, but locations are disputed.
      • There's supposedly an entire secret subway system under Moscow, bigger than the regular one and buried up to 200m underground, linking numerous important buildings and providing means for movement and evacuation of VIPs. Though, if the most popular purported map of the system is to be believed, it's only larger in the sense that some of its tunnels are significantly longer than the ones of the normal Metro — one of them supposedly reaches Vnukovo airport. Otherwise, there are few of them, and the tunnels and stations are narrow, undecorated, and spartan. The Metro 2 makes a prominent appearance in Metro 2033, where it allegedly has vaults full of pristine military equipment.
      • Some of the secret underground structures in Moscow have since been abandoned by the military and declassified, and one even turned into a museum.
      • Nobody seems to know what's under Mount Yamantau, but whatever it is, it's definitely huge.
      • Or not. Maintaining any large underground object would require much better logistical capabilities that could be provided by third-class narrow mountain road and long-defunct (and partially dismantled) railway, which seem to be the only roads near Yamantau.
      • Predating these all, by quite a long time, is Britain's series of bunkers inside the rock of Gibraltar.
    • Similar to the Greenbrier Resort is the Canadian Diefenbunkers
    • A few shots in the movie WarGames showed the actual Cheyenne Mountain complex. The NORAD room in that was a mock-up (the most expensive movie set ever at that time) and far more snazzy than the real one. This was due to the filmmakers having insufficient security clearance for the real one.
      • The Second-In-Command of NORAD is a Canadian (it's NORTH AMERICAN Air Defense, not American Air Defense) — and yet in all the movies set in Cheyenne Mountain, there is nary a Canuck in sight.
    • Also, Cheyenne Mountain is in Stargate SG-1 and Jeremiah (This one has the benefit of being a real complex). In the original movie Stargate, the Gate was hidden in the fictional Creek Mountain complex — also in Colorado, and to boot having recycled the Cheyenne Mountain entrance set from WarGames. The series retconned the Stargate's location without much fuss. To make Stargate Command, they added 2 fictional sub-floors to the real-life Cheyenne Mountain Complex. The complex itself is real, the extra floors housing Stargate Command aren't. Though, in the real complex, there is a door marked Stargate Command in homage to the series (since it was Backed by the Pentagon). It leads to a broom closet.
    • Raven Rock, most famous to gamers from Fallout 3, is a real base built for much the same purpose as Cheyenne Mountain.
    • Offutt Air Force Base is rumored to have an underground command center proof against anything short of a direct hit with a nuke. It's impossible to be certain because those chambers are not on the Official Elementary School Field Trip tour, they're still in use. (George W. Bush did not fly to Omaha on 9/11 because he wanted steak for lunch...)
    • After the Cold War, the Strategic Air Command bunker in Amherst, Massachusetts was put up for sale. Who besides the government could want an elaborate concrete bunker? Librarians, apparently; the Five Colleges bought it for cheap, and now use it for book storage. The low temperatures and lack of sunlight are ideal for preservation, and it's hard to beat the security.
    • Speaking of decommissioned bunkers and missile silos, there's a real estate company specialising in such properties.
  • After the First World War, the French built the Maginot Line on their border with Germany, a chain of defensive fortifications, most of which are underground, connected by underground tunnels with bunkers and living facilities. It was an amazing feat of construction. And ever after, people have caricatured it by pointing out that the Germans went around it—which is true but misleading, because that was the purpose of the Maginot Line.
    • Visitors to Eastern France intending to check out the Maginot Line are strongly advised that not all of it has been decommissioned and made redundant. Far from being a historical relic, many parts of the Maginot installations are still in use today by parts of the French armed forces who do not welcome casual visitors, such as the special forces and the nuclear weapons defence establishment.
      • With the end of the Cold War, only one part of the Maginot Line remains in use as of today (2014). It is the Ouvrage Hochwald, one of the larger fortresses on the Line, currently used as a hardened underground command center by the French Air Force.
  • For contrast, Britain had Kelvedon Hatch Nuclear Bunker, a base for the nation's power structure hidden beneath a nondescript house. Apparently, it was active until 1992 (but only ever activated once: not for a nuclear crisis but for the poll tax riots). This site has pictures of it. It's now a tourist attraction and the real command center is somewhere secret.
    • Has been used as a filming location.
    • London also had Churchill's Cabinet War Rooms under the Treasury building. Their existence was kept a secret until the 1980s when they were renovated and opened as a museum.
  • Switzerland has built and maintained an extensive system of fortifications, tunnels, living facilities, and storage facilities, much of it underground or at least dug deep into mountains, called the National Redoubt, dating back to late 19th century. In the 20th century, they enhanced such additions as underground/in-mountain hangars for their air force and built reinforced highways that can function as backup runways when the planes emerge.
  • The USSR had a secret underground submarine base on the Black Sea. It couldn't, however, fit the larger subs of The '80s, and was subsequently decommissioned. It now houses a museum of the former base.
  • Iran is currently trying to protect their nuclear program by having the dedicated facilities be hidden in a series of tunnels, making it significantly more complicated for anyone to bomb their reactors and centrifuges.
  • North Koreans with Nodongs have a vast network of tunnels and bunkers crisscrossing their mountainous country, which houses almost everything military-related, from bomb shelters to storerooms to arms factories and control centers, etc. Some of those bunkers conceal secret SAM installations, and some house the mobile launchers of their recently developed MRBMs/ICBMs, where they could be kept out of sight and possible bombing raids, but could be quickly brought out to bear. This alone makes a possible invasion a potential bloodbath of unimaginable proportions. They also had several underground tunnels built so their troops could surprise-invade South Korea when the time is right (or so the southerners think). In reality, most of those tunnels were used for the spy insertion and retrieval.
  • The archives, restoration and research workspaces, and other non-public facilities of the Smithsonian Institution's D.C. museums occupy a huge multi-level network of rooms and passages, which crisscross the National Mall and interconnect its various above-ground public buildings. Like most museums, the vast majority of the Smithsonian's historical, cultural, and scientific assets aren't on display.
  • The University of Illinois Undergraduate Library is entirely underground, save for two small entrances each about the size of a large trailer. It's awesome because they did this so that it would not cast a shadow on a nearby "historic" cornfield. Seriously, you can't make this stuff up.
    • The University of Illinois Chicago (UIC) has an elaborate network of steam tunnels off-limits to everyone except authorized employees due to potential danger... and that one time they were used as part of a Supervillain Lair in 2002. Mad Scientist Joseph Konopka (better known as Dr. Ch@os) escaped to Chicago to avoid facing prison in his home state of Illinois, and converted abandoned sections of the Chicago subway system in addition to the steam tunnels into his own lair. He was eventually caught by campus police during a stakeout after repeated use of the steam tunnels to conduct burglaries, and was turned over to the F.B.I.
  • The University Library of the University of Stellenbosch, South Africa, was built beneath the central green, as the land was donated on the condition of the green being a recreation area for the students. A bonus is that the entrance is actually underground as well, as it is dug down into a sort of amphitheater. Emergency exits and aircon vents still pop up here and there for safety.
  • The main stacks of Berkeley's central Doe Memorial Library take up about three stories below Memorial Glade (complete with skylights that are at ground level above).
    • This is a common strategy for large university libraries — Firestone Library at Princeton University has three underground stories (all much larger than the above-ground footprint) housing more than 70 miles of shelves.
  • The Cu Chi Tunnels in Vietnam are another great example and are almost the archetype of the EUB.
  • The term "undisclosed location" entered the public lexicon after US VP Dick Cheney was stated to be touring them after attacks on DC and New York. Because of his reputation, it is somewhat assumed that any use of the term implies this trope played to the hilt.
    • Conspiracy Theorists speculate about the existence of DUMB, or Deep Underground Military Base. It doesn't sound any more sinister than your regular well-protected military base, except that it's supposedly run by your favorite conspiracy (The Illuminati and Reptilian Conspiracy being a popular choice) and people are abducted and carried there for unspeakable purposes.
  • Željava Air Base in former Yugoslavia is the world's largest underground Air Base. While they still have overground runways, everything else is underground and has enough food, fuel, and ammo to survive 30 days without outside intervention. It has been, alas, demolished.
  • It happens in private as well. In 2005, Fred Strunk was sentenced to 18 years for running an elaborate pot growing operation in a cave in Tennessee.
    • and its subsequent owners found a pretty profitable use for it that's legal: its year-round consistent temperatures provide the perfect conditions in which to age cheese.
  • Julian Assange's Wikileaks facility in Stockholm, Sweden, located in a cold war era nuclear bunker.
    • It's just a web host. It doesn't belong to Assange.
  • In London, the underground railway linking Royal Mail facilities, is now closed, but documented by urban explorers.
  • Muammar Gaddafi, the former dictator of Libya, had a huge underground base hidden under Tripoli. Among other things, it contained an entire functioning hospital and stockpiles of food large enough for an entire city. It also had tunnels big enough to drive tanks through.
  • It is commonly speculated that Area 51 has a vast underground system where all the top secret research and technology development is made. From the surface there have been signs of hangars and Air Force bases but nothing truly out of the ordinary, this had led people to believe that there must be something underground they are hiding if the surface appears to be normal.
  • The Magic Kingdom at Walt Disney World famously has the utilidor system, a series of underground corridors in a ring around the park (plus a central corridor) that includes virtually all of the important employee areas and allows them to quickly move to any area of the park without being seen by guests in the wrong costume. Ironically, the utilidor technically isn't underground; Florida notoriously has a very high water table that makes it excessively difficult to build anything below ground, so the Magic Kingdom is actually built on a raised hill (made from the earth scooped out for the Seven Seas Lagoon) with the utilidor built at ground level.
  • Humans don't have a monopoly on this trope either; ants have been known to form some fantastically complex underground structures. If you think this one is impressive then the largest one known, under Hokkaidō, has an area of roughly 2.7 square kilometers.
  • Allegedly, Osama bin Laden's "command centre" in the caves of Tora Bora mountain was this, with reports of fully equipped hospitals, hydro-electric power stations, a hotel, a tank park, and facilities for 2000 men flying around prior to its capture by NATO forces during Operation Enduring Freedom. Turns out it was a system of natural caves, with a few small manmade connecting tunnels, housing 200 men at most, some middlingly sized ammunition depots, and rudimentary medical facilities run by The Dragon (Ayman al-Zahawiri is a qualified surgeon). Whilst possibly more impressive than usual guerilla hideouts, it hardly lived up to its hype.
  • The Large Hadron Collider in Switzerland certainly lives up to its name - at a depth of 175 meters with a circumference of 17 kilometers, it is both astoundingly large and astoundingly elaborate.
  • Much of the German-built Atlantic Wall was built underground. Several sections have been restored for tourists but even those that have been left to rot are often in good enough shape to visit.
  • A non-military example is the Leas Cliffe Hall in Folkestone, Kent, a 700-seater theatre/performance venue and conference center. Built-in the 1920s, the only obvious sign of its presence is a modestly sized pavilion and cafe on the promenade. However, go inside and follow the steps down. The theatre complex is actually built into the cliff — a westerly extension of the White Cliffs of Dover — and occupies several underground levels, with bars and terraces overlooking the English Channel. Elsewhere on this stretch of coast, the greater part of Dover Castle is a network of underground galleries and strongpoints built into the White Cliffs proper; it served as a major command centre in WW2, and its underground structure was greatly added to so as to protect it from German bombing and long-range artillery.
  • The Matshuhiro Underground Imperial Headquarters near Nagano was intended to be this for Imperial Japan as the Allies turned the tide of World War II — since Tokyo was on the coast, it would have been too risky to leave the central apparatus of the Japanese government there in the event of a US invasion. Construction began in November 1944 and it was about 75% complete when Japan surrendered the following August.
    • Tama Hills, an area in the foothills around Tokyo, was once home to a munitions factory and depot. While it wasn't one continuous underground facility, most of the buildings and storage areas were carved into the hills or buried in an attempt to protect it from aerial observation and attack, particularly a concern late in World War II. As it happens, it succeeded, and the Americans did not discover it until several months after Japan's surrender. It has since been decommissioned and converted into a golf course and campground for US military members and their families, with many of the original structures, tunnels, etc. still around, if badly overgrown with weeds and bugs.
      • Many Japanese island bases during World War II featured an extensive system of underground fortifications based on both natural caves and man-made tunnels — Iwo Jima, Pelilieu, Saipan, etc.
  • Svalbard Global Seed Vault in Norway is a massive storage facility with labs built into a mountain to preserve seeds in case wild and farmed species die off. Currently, it contains over 750,000 samples.
  • When the British started bombing the Germans' rocket works at Peenemunde in 1943, the entire manufacturing operation was moved to Mittelbau-Dora, a factory / concentration camp built in mountain tunnels in Thuringia. This was where the bulk of the V-1 and V-2 rockets were constructed. In contrast to the fanciful nature of the whole enterprise — secret underground Nazi rocket base! — the camp was a particularly brutal one, where one in three workers (about 20,000 in total) died... largely pointlessly since it turns out untrained, starving, and unenthusiastic slave workers aren't very good at making hi-tech stuff. In fact, more people died constructing and working in these factories than were killed by the weapons they manufactured.
  • The Führerbunker, where Hitler spent the last weeks of the war, was originally built to be a temporary air raid shelter. However, as the Allies pressed further into German territory, it was expanded into an improvised permanent shelter. By all accounts, it protected its inhabitants from the shelling outside.


Video Example(s):



The Mermalair level takes place in the Mermalair, surprise surprise, a parody of the deep dark Batcave.

How well does it match the trope?

5 (3 votes)

Example of:

Main / CreepyCave

Media sources: