[[quoteright:300:[[Film/YouOnlyLiveTwice http://static.tvtropes.org/pmwiki/pub/images/yolt3.jpg]]]]

->'''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.
-->-- ''VideoGame/SplinterCellChaosTheory''

%% One quote is sufficient. Please place additional entries on the quotes tab.

To maintain PlausibleDeniability and hide from magical TV SpySatellites, 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 AppliedPhlebotinum. AfterTheEnd, or in preparation for TheEndOfTheWorldAsWeKnowIt, openly known organizations may elect to move BeneathTheEarth as well. And it's a good location for a SupervillainLair.

The Elaborate Underground Base will generally have a [[TheWarRoom war room]], and may also include hangar space for HumongousMecha or a CoolStarship. Particularly large examples may be the size of [[UndergroundCity 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 [[AdventureTowns Adventure Town]]; the smaller ones are frequently the setting for a BottleEpisode. If it was built during the UsefulNotes/ColdWar, it may be YeOldeNuclearSilo.

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. [[FridgeLogic 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 UnderwaterBase, IslandBase, AirborneAircraftCarrier and SpaceBase. Not to be confused with UndergroundCity, which is built by civilians rather than a secretive organization. See BeneathTheEarth for a related phenomenon, minus the AppliedPhlebotinum. May induce SigilSpam if the organization really loves their logo.



[[folder: Anime and Manga]]
* United Earth Headquarters in ''Anime/AldnoahZero'' 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 AlternateHistory, the Soviet Union might not have collapsed and is still the ruling government of Russia.
* The Guild is a massive developed cave system controlled by Class SSS in ''Anime/AngelBeats''.
* In ''Manga/ArpeggioOfBlueSteel'', 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.
* One of ''Anime/{{Doraemon}}''`s future gadgets allow instant creation of one of these. It can be big enough to become a city of its own, which Nobita then exploit to create his own dictatorship (PlayedForLaughs). However, one of the movie deal with the sinister encounter with TheReptilians when Nobita and co DugTooDeep...
* Father, the BigBad of ''Manga/FullmetalAlchemist'' has the ''entire area underneath Central city!''.
* The Far East Branch of [[HeroesRUs AEGIS]] in ''VideoGame/GateKeepers'' 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 ''Manga/HighSchoolNinjaGirlOtonashiSan'' is a trap-filled underground lair that is otherwise decorated like a normal home.
* ''Anime/MazingerZ'':
** The Island of Bardos. Dr. Hell set his first base in the subterranean mazes of that island, building all what he needed for his SuperVillainLair: a war room for planning strategies, private chambers for his CoDragons, barracks for his {{Mook}}s, several hangars, laboratories to build weapons, HumongousMecha and cyborgs, training fields for his troops and {{Robeast}}s, 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?"
** ''Anime/GreatMazinger'': Mykene were a civilization had lived underground for millennia, so their entire empire -an intrincate network of caves and caverns- was an Elaborate Underground Base.
* Jaburo of ''Anime/MobileSuitGundam''. 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. Granted that it's only seen in a few episodes of the original series before being [[SelfDestructMechanism blown away]] in ''Anime/MobileSuitZetaGundam'', but it does get additional screentime in ''[[Anime/MobileSuitGundam0083StardustMemory Stardust Memory]]'' and ''[[Anime/MobileSuitGundamMSIGLOO MS IGLOO]]''.
* ''Anime/NeonGenesisEvangelion'' has NERV setting up shop inside the [=GeoFront=], a massive cavern that is actually just the upper 11% of an even larger spherical cave, [[spoiler: which is actually the buried remains of the object that [[{{Panspermia}} brought life to earth,]]]] almost completely filled up with earth and rock debris. And going UpToEleven, Terminal Dogma is an Elaborate Underground Base built below another Elaborate Underground Base.
* The [[Manga/SailorMoon manga]] and [[Series/PrettyGuardianSailorMoon live action]] versions of ''Franchise/SailorMoon'' have an underground base under the LocalHangout.
* Numerous Galactor bases on ''Anime/ScienceNinjaTeamGatchaman'' fall under this heading. By extension, enemy bases on the Americanized versions.
* The main characters' HQ in ''Anime/SenkiZesshouSymphogear''. [[spoiler:It's probably remnants of a {{Precursor}} race.]]
* Fairy Airbase in ''Franchise/SentouYouseiYukikaze'' 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 UndergroundCity where Fairy Air Force personnel live.
* ''Manga/SgtFrog'' has the home base of the Keroro Platoon which is built under the Hinata household, much to the chagrin of Natsumi and Fuyuki.
* The Steam Castle in ''Anime/{{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.
* ''Anime/SuperDimensionFortressMacross''/''{{Anime/Robotech}}'' has an underground base in Alaska (possibly in the site of the real life Elmendorf AFB), armed with the ''{{BFG}}'' of [[WaveMotionGun Wave Motion Guns]]. Incidentally, secondary ''Anime/{{Macross}}'' sources list four other identical bases being built when the Zentradi launch the final attack, one of them in the same area of [[Anime/MobileSuitGundam Jaburo]].
* The Autobots' base in ''Anime/TransformersCybertron''. 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.
* The EF HQ in ''Anime/AldnoahZero'' is so enormous that the large transport planes can maneuver safely within, and it can support thousands of personnel and refugees. It's been speculated by fans that it was built either in a former open pit coal mine that's been roofed over, or they've used one of the reservoirs created in TheSixties when the [[UsefulNotes/SovietRussiaUkraineAndSoOn Soviet Union]] experimented with improving the oil field productivity [[ILoveNuclearPower by the nuclear blasts]], the base being situated in the steppes of Southern Siberia.

[[folder: Comic Books]]
* The Batcave from the various ''Franchise/{{Batman}}'' series, an enormous cave containing a supercomputer, [[CoolGarage garage]], [[SuperheroTrophyShelf various trophies]], and basically everything else the Batfamily needs.
* In ''ComicBook/GothamCityGarage'', ComicBook/{{Supergirl}}, ComicBook/{{Nightwing}} and ComicBook/{{Catwoman}} break into a secret facility built by ComicBook/LexLuthor underneath a mountain where he fabricates his army of robotical enforcers.
* The original headquarters of the Franchise/{{Justice League|of America}} was an elaborate base built into the base of a mountain. Several other teams have taken this base out of mothballs, such as ComicBook/YoungJustice.
* ''ComicBook/PS238'', the school for children of superheroes, is in an Elaborate Underground Base beneath an ''actual'' elementary school.
* In ''ComicBook/ActionComics'' #271 ComicBook/{{Supergirl}} builds an underground base beneath the Arabian Desert, complete with guest and trophy rooms.
* Xavier's mansion of the ''Comicbook/XMen'' is usually presented as being only living quarters and classrooms for students and staff; the actual base of operations is underground.
* The ComicBook/{{Thunderbolts}} have their base located inside a mountain.
* ''GIJoe'' 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 ''[[TownWithADarkSecret entire town]]'' brimming with underground evil.
* During the Silver Age, Lex Luthor's "Luthor's Lairs" numbered in the hundreds, and could be found anywhere. At least one of them lasted until the 30th Century, showing up in a ''Comicbook/{{Legion Of Super-Heroes}}'' story where the outlawed Legionnaires make use of it to not only get new outfits again, but find out [[MassHypnosis what caused the populace to turn against them]].
* During the Hydra arc of [[ComicBook/JMSSpiderMan JMS's run on Spider-Man]], Peter wonders how ComicBook/{{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...it's...NON-UNION! The horror...the horror...''
* Creator/WarrenEllis' [[LampshadeHanging Hangs a Lampshade]] on the subject in ComicBook/AstonishingXMen #34 - ''then deconstructs it as grotesque with the very next sentence.''
-->'''ComicBook/{{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 ''Franchise/{{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.
* In ''ComicBook/SonicTheComic'' the Freedom Fighters used Kintobor's labtory containing living space, storage areas, monitoring equipment (which left plenty of screens on which to play videogames!), 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.
* The titular protagonist of the comic book ''ComicBook/{{Diabolik}}'' has ''a lot'' of these, each containing gadgets, laboratories, holding cells, spare [[CoolCar Jaguar E-Types]] and loot while he and his lover Eva live in the luxury homes built right on top of them.
* ''ComicBook/ScoobyApocalypse'' has the Complex, the massive underground lab facility in Nevada where Shaggy and Velma work at the start of the series.

[[folder: Fan Works]]
* ''Fanfic/DungeonKeeperAmi'' 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 DungeonPunk. Mecha? Check. Underground magical hudrophonics bays? Check. War Room? Check. SigilSpam? Check. Lacks a proper hangar for the [[{{CoolAirship}} airship fleet]], but one was actually an UnderwaterBase, and another an IslandBase...
* In the ''WesternAnimation/JackieChanAdventures'' and ''WesternAnimation/TeenTitans'' crossover fanfiction ''Fanfic/AShadowOfTheTitans'', there's the HIVE Academy like in canon, which Jade comments on being like Section 13, only with better aesthetic appeal.
* ''Fanfic/ChildOfTheStorm'':
** HYDRA probably had many, but after Operation Overlord and their being forced to retreat to one last base [[spoiler: 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 [[spoiler: Harry Dresden blew a very large hole in the catacombs and the street above]]. Now he's [[BasementDweller 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 Fanfic/{{the Calvinverse}}:
** Dr. Brainstorm of ''Fanfic/CalvinAndHobbesTheSeries'' used to have one of these, and it gets reactivated by [[spoiler: Holographic Retro]] in "Electric Invasion".
** The Lightning Man also has one in UsefulNotes/LasVegas, 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 super villain 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 RecursiveFanfiction ''Fanfic/ThePezDispenserAndTheReignOfTerror''.
* In ''FanFic/DeathNoteEquestria'', 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.
* ''FanFic/JewelOfDarkness'': Slade, as per canon, has a fondness for these, which [[DaddysLittleVillain Midnight]] seems to have picked up from him.
* In the Literature/{{Worm}} fanfic, ''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 [[EverythingsBetterWithDinosaurs Pangea Alliance]] in the MassEffect story ''FanFic/MesozoicEffect'' 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 [[HumanPopsicle cryosleep]], but eventually started building them on other worlds because of their defensive potential.

* Dr. Evil from ''Film/AustinPowers'' has an underground lair.
* ''Film/TheAvengers1998''. Sir August's underground base, which is on an island in the Thames in London.
* The HYDRA facilities in ''Film/CaptainAmericaTheFirstAvenger'' 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 ''Film/DangerDiabolik'' has a huge underground lair. The movie was shown as the last ''Series/MysteryScienceTheater3000'' episode:
--> '''Mike:''' Wow, occasionally a spelunker just wanders in: "Hey, what the hell?!"
* The majority of ''Film/DayOfTheDead1985'' takes place in a vast bunker as the scientists attempt to find a cure for zombies. Less elaborate that 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 ''Film/GIJoeTheRiseOfCobra''.
* In ''Film/{{Hellboy}}'':
** The headquarters for the Bureau of Paranormal Research and Defense is located underneath a nondescript government building.
** Rasputin has an underground lair [[spoiler: located under his mausoleum in Moscow]]
* ''Film/HollowMan'' - Secret underground lab [[spoiler: accessible by a single secure elevator, which Sebastian uses to trap his coworkers.]]
* District 13 in ''Film/TheHungerGamesMockingjayPart1'', 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. [[spoiler: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]].
* ''Film/TheIsland'': An underground base is used to [[spoiler:house clones who are led to believe that the outside is a wasteland]]. The lair is taken straight from the original comics (see ComicBook section above).
* ''Film/JamesBond'', amazingly enough, has very few of these, despite the series being ridden with cartoon villains and conspirators. The closest they ever got were the hollowed-out volcano complex in ''Film/YouOnlyLiveTwice'' and Drax's Amazon launch facility in ''Film/{{Moonraker}}''.
** ''Film/GoldenEye'' had an elaborate underground military bunker at Severnaya, and the BigBad's Lair is actually below the giant pool where the cradle antenna is hidden.
** ''Film/DrNo'' 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 ''Film/LiveAndLetDie'' had an underground base near one of his poppy fields in San Monique for processing the poppies' morphine into heroin.
* ''Film/KingsmanTheSecretService''
** The climax takes place in a bunker [[BigBad 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.
* ''Film/LogansRun'': The city's underground, anything from ruins to a gigantic freezer [[spoiler:full of the corpses of the Runners that made it out of the city]].
* Zion in ''Film/TheMatrix'' that is also a full blown city.
* The secret headquarters of the ''Film/MenInBlack'' are located several stories beneath Manhattan... accessible by the entrance to the Brooklyn-Battery Tunnel.
* In the sequel to ''Film/{{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.
* ''Franchise/ResidentEvil''
** The [[Film/ResidentEvil first film]] takes place in a massive laboratory hidden underneath Raccoon City. To help with the claustrophobia the walls have a city skyline on them and are covered by blinds.
** In ''Film/ResidentEvilExtinction'' [[EvilCorp Umbrella]] has moved all their staff to secured underground facilities due to the ZombieApocalypse.
* ''Film/SkyCaptainAndTheWorldOfTomorrow'' (2004). MadScientist Dr Totenkopf has a base populated by [[TheSwarm hordes]] of flying {{killer robot}}s that is large enough to contain a brobdingnagian RaygunGothic rocketship.
* ''Film/SkyHigh2005''. The Secret Sanctum.
* ''Film/THX1138'': Doesn't gets more elaborate than an entire undergound ''city''.
* Team America, in ''Film/TeamAmericaWorldPolice'', had an elaborate base ''inside Mount Rushmore''.
* ''Film/UndercoverBrother''. The BROTHERHOOD has an extensive base located beneath a barber shop.
* In ''Film/X2XMenUnited'' the underground base becomes a plot element when the SpySatellites actually detect the CoolShip in its hangar underneath the Mutant Academy. 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 mutantkind. Stryker's also got an Elaborate Underground Base of his own.
* ''Film/InvisibleInvaders'': 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 BMovie budget allows it to get, full of research equipment and with a large garage.
* The Film/{{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 CoolGarage 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).
* ''[[Film/{{Screamers}} Screamers: The Hunting]]''. The eponymous {{Killer Robot}}s are made in automated factories beneath the surface. The characters have an OhCrap reaction when they enter a shut-down factory and see just how ''big'' it is. Of course, someone [[IdiotBall inevitably does something stupid]] to cause it to power up again...

* The Wildfire facility in ''Literature/TheAndromedaStrain''. 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 ''Literature/{{Animorphs}}''
* The Alchemists' Guild in ''Literature/ASongOfIceAndFire'' has an elaborate underground Guildhall composed of a labyrinth of tunnels, cells, halls, and warehouses filled with highly explosive [[GreekFire wildfire]]. The place is designed to limit the damage should a cache of wildfire combust.
* Willy Wonka's crazy factory in ''Literature/CharlieAndTheChocolateFactory'' 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 ''Literature/ChungKuo'' 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 ''Literature/{{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 [[spoiler:know exactly where the base is - in their AugmentedReality 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 Creator/TerryPratchett's ''Literature/{{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 ''Discworld/{{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 debateable, 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 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.
* TheIlluminati's Bavarian headquarters in ''{{Literature/Duumvirate}}'' is one of these. Parts of it are a couple of centuries old.
* In the Creator/DaleBrown 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 [[CreatorProvincialism Scandinavian Mountains]]. In story, more installations were supposed to be built... but they were either unfinished or sabotaged when World War III came.
* Center, TheChessmaster AI of ''Literature/TheGeneral'' 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.
* The Ministry of Magic in ''Literature/HarryPotter'' is completely underground that can be reached via elevator telephone booth, flushing down magic toilets (no joke), Apparation or Floo powder.
* Creator/StephenieMeyer's ''Literature/TheHost''
* ''Literature/TheHungerGames'' gives us [[spoiler:District 13]], which is extraordinarily large.
* The sapient rats from ''Mrs Frisby And The Rats Of NIMH'' built themselves a MouseWorld version of this trope under the farm. No actual AppliedPhlebotinum is present by ''human'' standards, but by the standards of other animals it's a regular MadScientistLaboratory.
* In the Literature/DirkPittAdventures, Dirk Pitt has infiltrated his share of these.
* The Calvarians of ''Literature/TheReynardCycle'' 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 ''Literature/{{Redwall}}'' books.
* The Observatory in ''Literature/SeptimusHeap'' is heavily hinted at to be this.
* Supervillain Doctor Impossible of ''Literature/SoonIWillBeInvincible'' 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.
* In ''Literature/StarTrekTheGenesisWave'', the Lomarians (PlantAliens 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 Creator/KimNewman's short story "Literature/{{Swellhead}}", the ghostly remains of the ElaborateUndergroundBase of a supervillain from an AlternateUniverse is 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).
* Literature/TheThrawnTrilogy has the Mount Tantiss facility on Wayland.
* To a lesser extent, the cloning facility on Dantooine in ''Literature/GalaxyOfFear''.
* In the Literature/TimeScout series, half the action takes place on time terminal 86, in a winding cavernous complex in the heart of a Tibetan mountain in 1912.
* SuperheroSchool Whateley Academy in the Literature/WhateleyUniverse 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.
* Creator/JRRTolkien was big on these, for good, bad, and ambiguous guys.
** In ''Literature/TheHobbit'', you have dwarf Kingdom Under-The-Mountain in the Lonely Mountain (pwned by Smaug the dragon). In ''Literature/TheLordOfTheRings'' you have Khazad-dûm (Moria), the ancient dwarven country under the Misty Mountains. Dwarves in general prefer to live in these sorts of places. Even the Petty-dwarves have a hall under a large hill in ''Literature/TheChildrenOfHurin''.
** Morgoth, the BigBad of ''Literature/TheSilmarillion'' had [[{{Hell}} 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. Underground elves are rather unusual in fiction... perhaps the assumption that OurElvesAreBetter means they don't live in holes in the ground anymore. Only [[AlwaysChaoticEvil dark elves]] would do that sort of thing nowadays.
** ''The Silmarillion'' features Nargothrond (pwned by Glaurung the dragon) and Menegroth -- both were built with dwarven assistance, and very beautiful inside. ''The Hobbit'' also mentions Nargothrond's Noldor under the confusing appellation "deep elves" -- it refers to their "deep" knowledge rather than an established habit of living underground, which no elves demonstrate.
** ''The Hobbit'' also features the underground-dwelling Wood Elves of Mirkwood, who probably got the idea from Menegroth.
** 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. Their humble, homebody, rural-England aesthetic doesn't go with busy cities or ancient works of peerless engineering.
* In ''{{Literature/Doom}}: Hell on Earth'', the Mormons have built a sprawling bunker complex under Salt Lake City. [[LampshadeHanging Lampshaded]] by Fly when it reminds him of a ''Film/JamesBond'' movie.
* In ''{{Literature/Shatter Me}}'' Castle creates Omega Point, an underground city where people with gifts gather to plan a rebellion against the oppressive Reestablishment.
* In ''{{Literature/Remember To Always Be Brave}}''there are four of these. Three out of those are scenes of gory battles throughout the course of the book.
* Chrysalis Base from ''Literature/StarTrekTheEugenicsWars'' 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 to the scientists there.
* In the ''Literature/RiversOfLondon'' 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 [[VolcanoLair volcano]] away from being supervillains and b) watching the uniforms trying to secure the building gives the impression of a ClownCarBase. (This is TruthInTelevision, to the extent that some streets in Kensington actually have a serious subsidence problem.)

[[folder:Live-Action TV]]
* SHADO Headquarters in ''Series/{{UFO}}'' is located beneath a film studio. Think about it...
* The second season of ''Series/{{Space 1999}}'' saw the command team move from the above-ground "Main Mission" set to a "Command Center" located deep underground.
* Season four of ''Series/BuffyTheVampireSlayer'' 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 one also fits the trope.
-->'''Buffy:''' You said it was big. You didn't say it was ''huge''.
-->'''Riley:''' [[GettingCrapPastTheRadar I don't like to brag.]]
* ''Series/DoctorWho'':
** In the episode "The Runaway Bride", The Doctor finds an elaborate ex-Torchwood One research facility beneath the Thames river in London.
** Of course, that's far from the only ''Doctor Who'' example. In particular, the [[LizardFolk Silurians]] are fond of these.
** Also seen in ''The Sun Makers'', filmed in the real-life deep air raid shelters of London.
* Sheriff Jack Carter in ''Series/{{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 ''Series/HogansHeroes,'' 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. [[LampshadeHanging 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."
* Most of the Dharma stations on ''Series/{{Lost}}'' are partially or completely underground, and are of varying complexity. The Pearl and the Orchid are entirely underground. The Orchid is quite elaborate [[spoiler:and gives way to an even deeper cave containing the wheel which moves the island.]]
* Deep 13, from ''Series/MysteryScienceTheater3000'', supposedly. As noted, there is also one in the series finale, in the movie ''Film/DangerDiabolik.''
* Creator/NeilGaiman's ''Literature/{{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.
* ''Franchise/PowerRangers'' 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'' HumongousMecha ''and'' a CoolShip hidden inside.
* ''Franchise/SuperSentai'' used this in multiple series. [[Series/KyoryuSentaiZyuranger Zyuranger]], [[Series/ChourikiSentaiOhranger Ohranger]] and [[Series/TokumeiSentaiGoBusters 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.
* ''[[Series/MadanSenkiRyukendo Ryukendo]]'' has such a base hidden beneath a police station, accessed by praying to the elevator (really). It also serves as a HauntedHeadquarters.
* In ''Series/StargateSG1'', Stargate Command functions as an Elaborate Underground Base that includes a functioning interplanetary wormhole (see "RealLife" example, below). In later seasons, the "Alpha Site", "Beta Site" and "Gamma Site" are all built as copies of the SGC on other planets.
* The Genii of ''Series/StargateAtlantis'' act like SpaceAmish while actually living in these. Their true nature [[ContinuityDrift gradually becomes]] one of the worst-kept secrets in galaxy.
* The 60s series ''Series/TheTimeTunnel'' featured a colossal underground base that housed the titular TimeTravel device.
* Torchwood Three in ''Series/{{Torchwood}}'' is hidden under Roald Dahl Plass, Cardiff. This is in stark contrast to Torchwood One's tower in ''Series/DoctorWho'', 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!"
* M.I. 9 has an Elaborate Underground Base concelaed beneath St Hope's School in ''Series/MIHigh''. Given it houses only three operatives and their handler, it does seem somewhat like overkill.
* ''Series/TheAvengers'' episode "The Living Dead" had a huge underground city built by the villains for the purpose of raising an army.
* The ''{{Series/Dollhouse}}'' underneath Los Angeles is pretty much a self-sustaining spa eight stories down.
* Xenon Base in ''Series/BlakesSeven'' was an Elaborate Underground Base owned by a VillainOfTheWeek. 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.
* ''Series/{{Alias}}'':
** Season 4 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.
** ''Alias'' was always radically unrealistic...in an oddly gritty way. The first three seasons took a great deal of care that the actions and settings of the heroes and villains made sense ''on their own terms''. That is, given the weird premises of the setting, the actions and places made a great deal of logical sense. In Seasons Four and Five they threw all that aside and started making it all up as they went along, and it showed, as in nonsense like APO HQ.
** Case in point, in one scene in season 3, they're bringing a Master Villain (Arvin Sloane) into the Rotunda, the top secret HQ of a joint CIA/FBI/Other task force, and they made a visible point of locking all the computers, securing everything remotely 'sensitive', and the villain is brought in blindfolded and ear-plugged to keep the location and details secret from him. In season five, they bring the master villainess Irina Derevko, almost as dangerous as Sloane, into APO HQ with ''no precautions at all''. The writers just stopped trying or caring.
* Several appear on ''Series/{{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.
* ''Series/{{JAG}}: In "Sightings", the abandoned military airfield was built with underground aircraft shelters, being used by [[spoiler: drug runners]] to conceal their operation.
* The titular team in ''Series/MutantX'' 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.
* In the ninth episode of ''Series/StrikeBack: Project Dawn'', Scott and Stonebridge find their way into a system of Cold War-era underground bunkers, which the BigBad Latif was using as his base. Among the amenities are various storage, manufacture and testing facilities for WeaponsOfMassDestruction, 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 ''Series/{{Supernatural}}'' onwards, Sam and Dean have the [[AncientTradition Men of Letters]]' bunker.
* In ''Series/{{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.
* On ''Series/{{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.
* ''Series/PersonOfInterest'': From the fourth season onwards, Team Machine uses an abandoned subway station as headquarters.
* ''Series/AgentsOfSHIELD'':
** 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 onwards. As Coulson is reconciling with another branch, he uses this as a selling point towards peace.
--->'''Coulson:''' This way we can have a cool underground base ''and'' [[CoolBoat a boat]].
** In Season 3, [[NebulousEvilOrganization HYDRA's]] main base is a bunker revealed to be built underneath an abandoned oil refinery. Coulson [[LampshadeHanging 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 70's in case of nuclear war. It's so big and so well designed that in a BadFuture where [[EarthShatteringKaboom the Earth has shattered]], it functions as a perfectly habitable and self-sustaining space station.
* The Temple of the Cardinal Witches from ''Series/EmeraldCity''. 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 [[Recap/EmeraldCityS1E10NoPlaceLikeHome "No Place Like Home"]],[[spoiler:Dorothy either destroys or damage it heavily with the stone giant's sword in order to stop Glinda and her witches]].

* The Operations Center level in ''VideoGame/ThreeDUltraPinball''

[[folder:Puppet Shows]]
* Creator/GerryAnderson seems quite fond of this one.
** In ''Series/{{Joe 90}}'' the BIG RAT was located in a secret underground facility beneath Professor [=McClaine=]'s house.
** In ''Series/{{Stingray 1964}}'', during alerts the entire ''city'' of Marineville can descend into a secure underground facility on hydraulic jacks. (Just in case anyone thought ''Anime/NeonGenesisEvangelion'' did that first...)
** ''Series/{{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.

[[folder:Tabletop Games]]
* Alpha Complex from ''TabletopGame/{{Paranoia}}'' is usually an elaborate underground warren with all the super-science facilities you could ever need. [[note]]Then again, continuity has never been a big deal in ''TabletopGame/{{Paranoia}}'' so it can be a a domed city, underwater, whatever the GM desires.[[/note]]
* The dwarves of ''TabletopGame/{{Warhammer}}'' live in huge undergound cities, following the example set by Creator/JRRTolkien. And the [[RodentsOfUnusualSize Skaven]] live below those in big cities and tunnels that span every continent.
* ''TabletopGame/{{Warhammer 40000}}'' 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.
* Despite the name, virtually none of the "dungeons" in any ''TabletopGame/DungeonsAndDragons'' campaign are prisons. They're either natural caverns full of unintelligent monsters (rare), tombs full of undead (uncommon), or this trope for the VillainOfTheWeek (''extremely'' common).\\
Taking this to its logical extreme is [[http://images.yuku.com/image/pjpeg/45536ba641a897edcc85536f05a293fe97906a7c.jpg Malsheem,]] fortress of [[{{Satan}} Asmodeus]], [[GodOfEvil god of sin and tyranny]] and [[DemonLordsAndArchdevils 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.
* The entire raison d'etre of House Telamones, Nosferatu bloodline from ''TabletopGame/VampireTheRequiem''. 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 Jadeborn in ''TabletopGame/{{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-inventers-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.
* Classic ''TabletopGame/{{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.


* OlderThanTelevision: The prototypical Elaborate Underground Base may well be Erik's lair under the Paris Opera in the various incarnations of ''ThePhantomOfTheOpera''.


[[folder: Video Games ]]
* ''VideoGame/EvilGenius'' is entirely about building one of these.
* ''VideoGame/HalfLife'':
** 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 ''VideoGame/{{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.
** [[spoiler:In the end it takes an [[ItsTheOnlyWayToBeSure underground nuclear bomb]] to eliminate any remaining witnessess and all alien forces still inside the facility.]] Though that event might be [[CanonDiscontinuity 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).
* The Aperture Science Enrichment Center in ''VideoGame/{{Portal}}'' is located, per the [[AllThereInTheManual supplementary material]], in an abandoned salt mine in Cleveland, Ohio. ''VideoGame/{{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.
* The whole of ''VideoGame/BreathOfFireDragonQuarter'' takes place in a geofront like super cave.
%%* The ''VideoGame/DungeonKeeper'' series.
%%* ''VideoGame/EvilGenius''
* ''VideoGame/DwarfFortress'': Although you don't technically ''have'' to do that (one of the DF Wiki's "optional goals" is to create a fortress that is based entirely around surface structures).
%%* ''VideoGame/{{Minecraft}}''
* ''VideoGame/BioShock1'' 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.
* ''VideoGame/CityOfHeroes'':
** 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 [[AlienInvasion Rikti]], and even the evil cultist Circle of Thorns have their ancient underground city. The Faultline zone (former ScrappyLevel RescuedFromTheScrappyHeap) 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.
* ''Franchise/{{Pokemon}}'':
** ''VideoGame/PokemonRedAndBlue'' and ''[[VideoGame/PokemonGoldAndSilver 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 ''VideoGame/PokemonColosseum'' and ''VideoGame/PokemonXDGaleOfDarkness'' 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 ''VideoGame/PokemonRanger'', where the Go-Rock Squad's base is underground in a mountain.
** It continues in ''VideoGame/PokemonRubyAndSapphire'' 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.
** ''VideoGame/PokemonXAndY'' has one Team Flare base under Lysandre Cafe and one underground at Geosenge Town.
* The ''VideoGame/NoOneLivesForever'' 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 2nd had an underwater base you had to infiltrate.
* ''VideoGame/CommandAndConquer'':
** 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 ''VideoGame/CommandAndConquerRedAlert'', there were the beautiful and famed internal missions. With computer consoles that actually did things.
** The ''VideoGame/TwistedInsurrection'' mod for ''VideoGame/CommandAndConquerTiberianSun'' also features several missions taking place in underground facilities.
* From the ''VideoGame/{{Fallout}}'' {{RPG}}s, the various Vaults.
** ''VideoGame/{{Fallout 1}}'' had the Glow, the Mariposa Military Base and the Brotherhood's Lost Hills HQ.
** ''VideoGame/{{Fallout 2}}'' had the Sierra Army Depot and the Hubologist base. The Brotherhood bunkers in the Den, NCR and San Francisco might also count.
** ''VideoGame/{{Fallout 3}}'' had Raven Rock and the Rockland comm. facility.
** ''VideoGame/{{Fallout 4}}'' has [[BigBad The Institute]], which is ''so'' elaborate that [[spoiler:the only way to access it is through {{teleportation}}.]]
** ''VideoGame/FalloutTacticsBrotherhoodOfSteel'' had the Brotherhood bunkers and Vault 0 which was simply the Cheyenne Mountain Complex coverted into an even larger facility.
** ''VideoGame/FalloutNewVegas'' has several: the Brotherhood, as usual, lives in an underground bunker, the Enclave remnants keep their PoweredArmor and [[CoolPlane vertibird]] in one, and Mr. House has a MechaMooks 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 Scientist}}s there blew the top off of it.
* In ''VideoGame/{{Wasteland}}'', as well as ''VideoGame/Wasteland2'', 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.
* ''[[VideoGame/FirstEncounterAssaultRecon 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 [[EarthShatteringKaboom 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.
* ''VideoGame/FinalFantasyV'' had the Catapult, an underground/underwater base of LostTechnology. 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.
* The entirity of ''VideoGame/OverBlood'' takes place in one.
* ''VideoGame/GearsOfWar'' 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.
* ''Franchise/{{Halo}}'':
** ''VideoGame/{{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 BridgeBunnies.
** ''VideoGame/HaloReach'': 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.
* ''VideoGame/Metro2033'' features the entire subway system of Moscow, [[AfterTheEnd which is home to the remnants of civilization.]] It also features huge military installations even below that.
* In ''Franchise/ResidentEvil'', 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 ''VideoGame/{{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.
* ''VideoGame/SkiesOfArcadia'' has elaborate underground bases for both the heroes and the villains.
* ''VideoGame/WorldOfWarcraft'':
** The Dark Iron Dwarves have their own underground base in Blackrock Mountain. Technically so does the Dark Horde and Nefarian, since their towering base is built ''inside'' a volcano's cone.
** The Defias Brotherhood has the extensive Deadmines, a combination mining facility, smelter, sawmill, and wetdock.
** 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.
* In ''VideoGame/ThiefIITheMetalAge'', 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 IslandBase and Elaborate Underground Base tropes.
* ''Franchise/XCom'':
** 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 [[spoiler: main base at Cydonia]]. Crosses over with UnderwaterBase 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, 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.
* ''VideoGame/DeusEx'':
** The first game concludes in [[spoiler:Bob Page]]'s base beneath Area 51. On the good side, Tracer Tong has a sophisticated laboratory several floors beneath his [[TheTriadsAndTheTongs Triad's]] compound.
** UNATCO Headquarters is itself underground, with [[spoiler:an MJ12 base]] beneath it. Yes, the game has an example of [[UpToEleven an underground base beneath another underground base.]]
** UNATCO Headquarters makes a return appearance in ''VideoGame/DeusExInvisibleWar''.
** ''VideoGame/DeusExHumanRevolution'' features several underground bases - a FEMA facility, the Harvesters' hideout, and [[spoiler:Panchaea]] to name a few.
* ''Franchise/TheElderScrolls''
** In the backstory, the [[OurDwarvesAreDifferent Dwemer]] combined this with AdvancedAncientAcropolis, building their complex and [[SteamPunk technologically]] [[{{Magitek}} 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 [[RagnarokProofing preserved states]] and {{Eternal Engine}}s 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 [[RealityWarper bending the laws of physics and nature]].)
** ''[[VideoGame/TheElderScrollsIIIMorrowind 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 afore-mentioned Dwemer ruins are also typically built into the ground.
** In ''[[VideoGame/TheElderScrollsIVOblivion 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.
** ''[[VideoGame/TheElderScrollsVSkyrim 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 SlaveRace, the Falmer. The Falmer are also shown to be capable of constructing elaborate networks of suspended bridges and platforms.
* The area under the Optimology building in ''[[VideoGame/ChzoMythos 6 days a Sacrifice]]'' counts.
* In ''[[Videogame/GabrielKnight Gabriel Knight: Sins of the Fathers]]'', the voodoo cartel has a temple doubling as their headquarters [[spoiler:under Jackson Square]]. It's hinted to have been built in the 19th century when [[spoiler: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.
* In the first ''Videogame/MegaManZero'' game, the LaResistance's base is located underneath an abandoned city. While the "base" itself is run-down, there are 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 ''VideoGame/MegaManX7''.
* Most Space Pirate bases in ''Franchise/{{Metroid}}'' games tend to be these. Probably because both their homeworld and their main base at Zebes are plagued by near-constant acid rain.
* ''VideoGame/ShadowComplex'' is a {{Metroidvania}} game that takes place in one gigantic base.
* Naoto's dungeon in ''VideoGame/{{Persona 4}}'' is one of these.
* The Alpha Protocol base in, well, ''VideoGame/AlphaProtocol'' 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. [[spoiler: 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.]]
* ''VideoGame/ColossalCave'', including the maze of twisty little passages, all alike.
* The ''VideoGame/{{Zork}}'' games take this to an extreme, what with most of the games taking place mostly in the Great Underground Empire.
* Fort Schmerzen in ''VideoGame/MedalOfHonor'' and ''Allied Assault''.
* The Descent series 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.
* ''Franchise/MetalGear'':
** In ''VideoGame/MetalGear'' and ''VideoGame/MetalGearSolid'', the titular HumongousMecha is hidden in one of these.
** ''VideoGame/MetalGear2'' 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 ''VideoGame/MetalGearSolidPortableOps'', 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: [[spoiler: 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 ''VideoGame/MetalGearSolidPeaceWalker'', 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.
* The Ancients in (old verse) ''VideoGame/MightAndMagic'' 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''.
* In ''VideoGame/GrandTheftAutoSanAndreas'', Carl must infiltrate one of these under a base called Area 69. Yes, it's inspired by Area 51 (see below).
* ''VideoGame/SaintsRow2'' features a base called [[spoiler:The Pyramid]] hidden under [[spoiler:a mountain]]. Amazingly, the company that built it was [[spoiler: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."
* In ''SidMeiersAlienCrossfire'', the Human Hive faction's bases (equivalent to cities in ''VideoGame/{{Civilization}}'') are stated in the fluff to be of the underground kind.
* In ''VideoGame/WinBack'', the GULF control center is hidden beneath a factory and office building.
* The Russian missile base in the last act of ''VideoGame/ModernWarfare'', which is also YeOldeNuclearSilo.
* The moonbase setting of ''VideoGame/{{Bioforge}}'', complete with hangar bay, cryogenics lab, prison, defense tower, medical experimentation lab.
* The majority of ''VideoGame/StillLife2'' is set in an unassuming house in the woods. The house is substantially larger than it appears due to the expanded atomic shelter underneath.
* ''VideoGame/{{MOTHER}}'':
** The fangame ''[[VideoGame/CognitiveDissonance MOTHER: Cognitive Dissonance]]'' has one on Mars that helps make Starmen.
** ''VideoGame/{{EarthBound}}'' has a huge base under Stonehenge in Winters.
* Underground Laborotories and Subterranian Complexes in ''VideoGame/ClickingBad''.
* ''VideoGame/CarmenSandiegoMathDetective'': The game opens with you infiltrating one used by VILE.
-->'''Chase Devineaux''': ''[whistles]'' Some new headquarters! Carmen's really outdone herself.
* ''VideoGame/Rayman3HoodlumHavoc'': 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 TempleOfDoom inside it too though.
* ''VideoGame/TheTuringTest'': Most of the game takes place in an underground complex located below the icy surface of Europa.
* In ''Videogame/{{Hitman 2016}}'', [[EvilutionaryBiologist 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.
* ''VideoGame/TheWitness'': [[spoiler:The high-tech complex inside the mountain]].
* ''VideoGame/TheSecretWorld'':
** TheIlluminati 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 MadScientistLaboratory, 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 [[PathOfInspiration 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 [[TrackingChip 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. [[spoiler: 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 EvilTowerOfOminousness 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 HumongousMecha to clog the streets of Tokyo if need be.

[[folder: Visual Novels ]]
* ''VisualNovel/{{Virtues Last Reward}}''[[spoiler: takes place in one of these, but ON THE MOON.]]
* Tokugawa's secret warehouse on the moon in ''VisualNovel/{{Policenauts}}''.

[[folder: Web Comics ]]
* In ''{{Webcomic/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 [[BasementDweller living in his mother's basement]].
* Seems to be the basic design for all Orsintos laboratories in ''Webcomic/SluggyFreelance''. Surprisingly, there's been nothing so far to suggest that [[OmniscientCouncilOfVagueness Hereti-Corp]] has one of these. As it turns out, [[spoiler:Dr. Steve's Baselab was designed to burrow underground.]]
* The main characters of ''Webcomic/ThePocalypse'' have a base placed under a supermarket in a city.
* ''Webcomic/TimesLikeThis'': It may ''technically'' be an Elaborate Underground Base, since it's run by a multination secret-service consortium, but [[http://timeslikethis.com/index.php?id=443 Paratopia]] is actually an underground Club Med-type getaway roughly the size of Delaware.
* In ''Webcomic/{{SSDD}}'' 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.
* ''Webcomic/EverydayHeroes'':
** While the main office is above ground, the training room is in [[http://eheroes.smackjeeves.com/comics/1895720/low-humor/ the sub-sub-basement.]] Also, M.W.A.H.A.H.A.H.A.H.A.H.A. headquarters is [[http://eheroes.smackjeeves.com/comics/2133415/ch12-06/ underground.]]
** While it's hardly elaborate, Hornswoggle and family live underground in a section of the sewers [[http://eheroes.smackjeeves.com/comics/2162218/home-deep-home/ fitted out like a typical apartment.]]
* The military base where the [[HalfHumanHybrid Chio]] were created in ''Webcomic/{{Follower}}'' is one of these. Aside from the hangars, most of the base appears to be underground.

[[folder: Web Original ]]

* In the ''Roleplay/GlobalGuardiansPBEMUniverse'', most of the [[DiabolicalMastermind Evil Overlords]] and [[EvilOverlord Diabolical Masterminds]] have one of these. The most notable example might be [[NebulousEvilOrganization TAROT's]] primary base in the United States. It is a multi-level complex located four stories beneath the Pentagon's lowest level, and is entered through a secret elevator located in that building. The fact that Federal law enforcement agencies would never think to tear the Pentagon apart looking for it amuses The Emperor greatly.
* The eponymous ''Roleplay/{{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 ''Roleplay/DarwinsSoldiers'' is an underground military research base. It is not really "hidden" per se, though as quite a bit of above ground infrastructure is present.
* ''Podcast/RandomAssault'': 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 [[TeleportersAndTransporters a series of rifts]] to travel to the mansion from their respective living places around the world.

[[folder: Western Animation ]]

* In ''WesternAnimation/TeenTitans'', 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 Series/{{Thunderbirds}} could well be the TropeCodifier.
* In a series full of {{Supervillain Lair}}s to begin with, in the ''Birdman'' episode ("Number One") that brought them into the open and really defined them as a threat, [[NebulousEvilOrganisation F.E.A.R.]] turned out to have one of these. One also appeared in the episode "The Quake Threat" (belonging to Dr. Kiroff).
* In the ''WesternAnimation/ChipNDaleRescueRangers'' 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.
* ''WesternAnimation/{{Dangermouse}}'' lived in an underground base in postbox on Baker Street in London, the same road as Sherlock Holmes.
* Vlad built himself one in ''WesternAnimation/DannyPhantom'' by the beginning of Season Three. Through an alternate universe, the underground base was a {{Foreshadowing}} element in a previous episode. [[ExecutiveMeddling Too bad he didn't find the time to put it to good use]].
* ''WesternAnimation/DextersLaboratory'', though how underground the lab is isn't really gone into, mostly due to physical impossibility.
* Gummi Glen in ''WesternAnimation/AdventuresOfTheGummiBears''. This version distinguishes itself by its surprisingly realistic take of 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.
* Syndrome has an absolutely awesome underground base in ''WesternAnimation/TheIncredibles'', complete with the 50's-60's Tiki/Googie/Art Deco look. Egg shell people-movers, yeah! Don't forget, it was built ''inside an active volcano''.
* ''WesternAnimation/JackieChanAdventures'' 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 what ever {{MacGuffin}}s were being [[GottaCatchThemAll collected]] that season. Could be reached via a phonebooth elevator or "the stairs".
* Global Justice headquarters, and several of Drakken's lairs, in ''WesternAnimation/KimPossible'', which also has a twist on the trope: Frugal Lucre's lair [[BasementDweller in his mom's basement]]. Also, a few of the locations that Drakken raids are themselves underground bases. Case in point, the episode where he steals some {{HypnoTrinket}}s had him raiding a base in the ColdOpening that was built underneath a desert, and [[AllDesertsHaveCacti a conspicuous cactus]] acted as a card key scanning device to grant entry.
* The ''WesternAnimation/RoadRovers'' 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.
* The ''WesternAnimation/SWATKats'' have a base hidden beneath the CoolGarage where they live and work.
* The Franchise/TeenageMutantNinjaTurtles live in a hideout within the sewers of New York City.
* Don't forget about the Labyrinth in ''WesternAnimation/{{Gargoyles}}''. Or the base Hacker dug out for himself in an episode of Cyberchase. He abandoned it by the next episode, though.
* ''WesternAnimation/JonnyQuest'' TOS.
** "The Dreadful Doll" has an arms and 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.
* In ''WesternAnimation/TheSimpsons'', 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.
* ''WesternAnimation/AvatarTheLastAirbender''. The [[SecretPolice Dai Li]] had a undergound base under a lake.
* Perry The Platypus has one underneath WesternAnimation/PhineasAndFerb's house, and the rest of the [[FunWithAcronyms OWCA]] base seems to run beneath all of the Tri-State area. ''All'' of it.
* Hedgequarters from ''WesternAnimation/TheMysteriesOfAlfredHedgehog'' is a benign junior version of this trope.
* ''WesternAnimation/SuperFriends'' 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.
* WesternAnimation/InvaderZim 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.


[[folder: Real Life ]]

* Underground command-and-control centers started getting popular sometime after UsefulNotes/WorldWarI, and much more so after nuclear weapons and [=ICBM=]s. [[http://www.greenbrier.com/site/bunker.aspx Greenbrier Resort]] was the site of a [=US Congressional=] command center for 30 years, until [[http://www.washingtonpost.com/wp-srv/local/daily/july/25/brier1.htm a Washington Post reporter exposed its existence in 1992.]] Cheyenne Mountain, Colorado, is quite famous as the "brain" of [[http://en.wikipedia.org/wiki/NORAD NORAD]] ([=NORth-american Air Defense=]), [=SAC=] (Strategic Air Command, bombers and land-based [=ICBM=]s) and the US Space Command (more to do with satellites, though). The latter two are now defunct, absorbed into other organisations. 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 [[http://en.wikipedia.org/wiki/White_House_Situation_Room 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 [[http://en.wikipedia.org/wiki/Moscow_Metro_2 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 a 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 ''Videogame/{{Metro 2033}}'', where it is 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 [[http://en.wikipedia.org/wiki/Mount_Yamantau Mount Yamantau]], but whatever it is, it's definitely '''huge'''.
*** Predating these all by, quite a long time, is Britain's series of bunkers inside the rock of UsefulNotes/{{Gibraltar}}
** Similar to the Greenbrier Resort are the Canadian [[http://en.wikipedia.org/wiki/Diefenbunker Diefenbunkers]]
** A few shots in the movie ''Film/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 film-makers having insufficient security clearance for the real one.
*** The Second-In-Command of NORAD is a Canadian (it's NORTH AMERICAN Air Defence, not American Air Defence) - and yet in all the movies set in Cheyenne Mountain there is nary a Canuck in sight.
** Also, Cheyenne Mountain is in ''Series/StargateSG1'' and ''Series/{{Jeremiah}}'' (This one has the benefit of being a real complex). In the original movie ''Film/{{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 ''Film/WarGames''. The series retconned the Stargate's location without much fuss.
** Raven Rock, most famous to gamers from ''VideoGame/{{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. (UsefulNotes/GeorgeWBush 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 [[http://www.missilebases.com/ real estate company]] specialising in such properties.
* After the First World War, the French built the UsefulNotes/MaginotLine 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 [[UsefulNotes/MaginotLine 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). [[http://www.muddyclay.com/october.htm This site]] has pictures of it. It's now a tourist attraction and the real command centre is somewhere secret.
** Has been used as a filming location.
*** Tourist signs directing people to it clearly say "[[http://russelldavies.typepad.com/planning/images/secret_nuclear_bunker-thumb.jpg Secret Nuclear Bunker]]".
** 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.
* [[UsefulNotes/SwissWithArmyKnives 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 it 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 TheEighties, and was subsequently decommissioned. In now houses a museum of the former base.
* Iran is currently trying to protect their nuclear program [[http://www.nytimes.com/2010/01/06/world/middleeast/06sanctions.html?pagewanted=3&hp 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.
* UsefulNotes/NorthKoreansWithNodongs have a vast network of tunnels and bunkers crisscrossing their mountainous country, which houses most everything military-related, from bomb shelters to storerooms to arms factories and control centers, etc. Some of those bunkers conceals secret SAM installations, and some house the mobile launchers of their recently developed [=MRBMs=]/[=ICBMs=], where they could be kept out of sight [[DeathFromAbove 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, the most those tunnels were used for was 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 flies straight into CrazyAwesome territory when you find out they did this so that it would not cast a shadow on a nearby "historic" cornfield. Seriously, you can't make this stuff up.
* In a similar vein, 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, though.
* The main stacks of [[StrawmanU 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 [[MemeticMutation public lexicon]] after US VP Dick Cheney was stated to be touring them after attacks on DC and New York. Because of [[StrawmanPolitical his reputation]], it is somewhat assumed that any use of the term implies this trope played to the hilt.
** {{Conspiracy Theorist}}s [[EpilepticTrees 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 (TheIlluminati and TheReptilians being 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 [[http://sparkreport.net/2009/03/the-full-story-behind-the-great-tennessee-pot-cave/ 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.
* [[http://www.youtube.com/watch?v=qwlATf9xse4 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 [[http://www.silentuk.com/?p=2792 underground railway]] linking Royal Mail facilities, 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 [[Ride/DisneyThemeParks 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 [[http://www.youtube.com/watch?v=lFg21x2sj-M fantastically complex underground structures]]. You think this one is impressive then the largest one know, under Hokkaidō, has an area of roughly 2.7 square kilometers.
* Allegedly, UsefulNotes/OsamaBinLaden'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 for 200 men ''at most'', some middlingly sized ammunition depots, and rudimentary medical facilities run by TheDragon (Ayman al-Zahawiri is a qualified surgeon). Whilst possibly more impressive than usual guerilla hideouts, it hardly lived up to its hype.
* The [[http://en.wikipedia.org/wiki/Large_hadron_collider 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 [[http://en.wikipedia.org/wiki/Atlantic_wall 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 centre. Built in the 1920's, 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 UsefulNotes/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 UsefulNotes/ImperialJapan as the Allies turned the tide of UsefulNotes/WorldWarII - 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 UsefulNotes/WorldWarII. 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, [[RuinsOfTheModernAge if badly overgrown with weeds and bugs.]]
*** Many of Japanese island bases during UsefulNotes/WorldWarII 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 were 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.
* The ''Führerbunker'', where Hitler spent the last weeks of the war, was originally built to be a termporary 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.