Elaborate Underground Base
: Who are you? Sam Fisher
: I'm the guy who's here to save the world. JGSDF Soldier
: I thought I was the good guy.... Sam Fisher
: No, no. You're on the team with the super-secret underground base. I'm the guy breaking into the base. That makes me the good guy.
To maintain Plausible Deniability
and hide from magical TV Spy Satellites
, any sufficiently powerful or advanced covert organization of heroes, villains, conspirators, or military personnel needs an Elaborate Underground Base to use as their headquarters and hide their Applied Phlebotinum
. After the End
, or in preparation for The End of the World as We Know It
, openly known organizations may elect to move Beneath the Earth
as well. And it's a good location for a Supervillain Lair
The Elaborate Underground Base will generally have a war room
, and may also include hangar space for Humongous Mecha
or a Cool Starship
. Particularly large examples may be the size of an entire city
, and might include hydroponics bays for growing food or even actual fields of crops lit by sun lamps. The larger sizes of Elaborate Underground Base frequently serve as an Adventure Town
; the smaller ones are frequently the setting for a Bottle Episode
. If it was built during the Cold War
, it may be Ye Olde Nuclear Silo
Particularly secretive organizations may hide their Elaborate Underground Base in the middle of a city, and include lots of elevators, trams, pneumatic tubes, and other means of transportation between the base and hidden chambers in buildings on the surface. How exactly such an extensive base can be built in secret
(among other things, all the excavated rock and dirt have to go somewhere
) is very rarely addressed.
Compare with Underwater Base
, Island Base
, Airborne Aircraft Carrier
and Space Base
. Not to be confused with Underground City
, which is built by civilians rather than a secretive organization. See Beneath the Earth
for a related phenomenon, minus the Applied Phlebotinum
. May induce Sigil Spam
if the organization really loves their logo.
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Anime and Manga
- Neon Genesis Evangelion has NERV setting up shop inside the GeoFront, a massive cavern that is actually just the upper 11% of an even larger spherical cave almost completely filled up with earth and rock debris. And going Up to Eleven, Terminal Dogma is an Elaborate Underground Base built below another Elaborate Underground Base.
- The Island of Bardos from Mazinger Z: Dr. Hell set his first base in the subterranean mazes of that island, building all what he needed for his Super Villain Lair: a war room for planning strategies, private chambers for his Co-Dragons, barracks for his Mooks, several hangars, laboratories to build weapons, Humongous Mecha and cyborgs, training fields for his troops and Robeasts, his throne room...
- Dr. Kabuto's lab basement also counts. It was hilariously lampshaded by Kouji in the original manga (since Juzo had built Mazinger Z in his home in the middle of a city whereas his anime version did it in his mansion located in Mount Fuji), when he found the entrance and asked: "Since when is there a basement in the garden?"
- Great Mazinger: Mykene were a civilization had lived underground for millennia, so their entire empire -an intrincate network of caves and caverns- was an Elaborate Underground Base.
- Jaburo of Mobile Suit Gundam. Granted that it's only seen in a few episodes of the original series before being blown away in Mobile Suit Zeta Gundam, but it does get additional screentime in Stardust Memory and MS IGLOO.
- Numerous Galactor bases on Science Ninja Team Gatchaman fall under this heading. By extension, enemy bases on the Americanized versions.
- Father has the entire area underneath Central city!
- The manga and live action versions of Sailor Moon have an underground base under the Local Hangout .
- Macross/Robotech have an underground base in Alaska (possibly in the site of the real life Elmendorf AFB), armed with the BFG of the Wave Motion Guns. Incidentally, Macross' secondary sources list four other identical bases being build when the Zentradi launch the final attack, one of them in the same area of Jaburo.
- The Autobots' base in Transformers Cybertron. 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.
- One of 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 (Played for Laughs). However, one of the movie deal with the sinister encounter with The Reptilians when Nobita and co Dug Too Deep...
- The main characters' HQ in Senki Zesshou Symphogear. It's probably remnants of a Precursor race.
- Fairy Airbase in Sentou Yousei Yukikaze is a mixed bag, in that much of the base is aboveground, but a significant portion of the facilities and hangars are located underground, such as the Special Air Force's hangar and support facilities. There's even an Underground City where Fairy Air Force personnel live.
- In Arpeggio of Blue Steel, the Japanese Navy is shown to have an underwater dock at Yokosuka Naval Base, built to protect what's left of the Japanese Navy's fighting ships from the Fleet of Fog. There's also the base I-401 maintained at Iwo Jima.
- Sgt. Frog has the home base of the Keroro Platoon which is built under the Hinata household, much to the chagrin of Natsumi and Fuyuki.
- The Far East Branch of AEGIS in Gate Keepers is found underneath a Japanese high school, because all the Gatekeepers in Japan are teenagers. It has secret entrances in all sorts of places, and the hangar is located underneath the lobby.
- The Batcave from the various Batman series.
- The original headquarters of the Justice League was an elaborate base built into the base of a mountain. Several other teams have taken this base out of mothballs, such as Young Justice.
- PS238, the school for children of superheroes, is in an Elaborate Underground Base beneath an actual elementary school.
- Xavier's mansion of the X-Men is usually presented as being only living quarters and classrooms for students and staff; the actual base of operations is underground.
- The Thunderbolts have their base located inside a mountain.
- G.I. Joe is rife with these. The original Joe base, "The Pit", is hidden underneath the chaplain's assistants' motor pool at Ft. Wadsworth in Staten Island. When this is destroyed by Cobra, a new Pit is built out in the desert. And Cobra has a fair number of secret bases themselves, including an entire town brimming with underground evil.
- 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 Legion of Super-Heroes story where the outlawed Legionnaires make use of it to not only get new outfits again, but find out what caused the populace to turn against them.
- During the Hydra arc of JMS's run on Spider-Man, Peter wonders how HYDRA can build one of these in New York while it's taken the city three extra months to finish a subway extension.
Unless...this whole thing, it's...it's...NON-UNION! The horror...the horror...
- Warren Ellis' Hangs a Lampshade on the subject in Astonishing X-Men #34 - then deconstructs it as grotesque with the very next sentence.
Cyclops: Our antagonist has serious infrastructure. I have a feeling we're going to see a classic James-Bond-Villain Crazy-Man base make itself known in a few moments.
Beast: I'm always up for a Doctor Crazy-Pants volcano headquarters.
Cyclops: This is the bit that really annoys me. All the things in this world that can be fixed with money? And every time it's "Well, I've got all this cash, but I bought myself an asteroid hideout instead."
Beast: Aaah. That, my friend, is indeed classic.
- In the Zorro comics written by Don McGregor (for Topps and Dynamite), Zorro has an elaborate underground base that rivals the Batcave.
- This is appropriate, as the Batcave was actually inspired by Zorro's hideout, both in and out of universe.
- In Sonic the Comic 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 Diabolik has a lot of these, each containing gadgets, laboratories, holding cells, spare Jaguar E-Types and loot while he and his lover Eva live in the luxury homes built right on top of them.
- The Wildfire facility in The Andromeda Strain. The only entrance is the elevator shed, and the facility topside is what it's disguised as - a wheat modifying facility.
- The Yeerk Pool in Animorphs
- The Alchemists' Guild in A Song of Ice and Fire has an elaborate underground Guildhall composed of a labyrinth of tunnels, cells, halls, and warehouses filled with highly explosive wildfire. The place is designed to limit the damage should a cache of wildfire combust.
- Willy Wonka's crazy factory in Charlie and the Chocolate Factory is mostly underground. The book contains an explicit explanation of this by Wonka, where he tells everyone that he decided to expand his factory by tunnelling downward and outward so that he could basically expand indefinitely. (Fridge thinking suggests that he wouldn't have to buy any more land or pay any rent to the property owners most of his factory is under, either; this would of course be all kinds of illegal in real life, but Wonka likely doesn't care.)
- David Wingrove's Chung Kuo has a series of underground bases in the Alps, the only part of Europe that is not occupied by the City or its plantations
- The government's Daemon task force base is largely underground. The trope is subverted (in a moment that is simultaneously hilarious and horrifying) in that the Daemon's operatives know exactly where the base is - in their Augmented Reality goggles there is a huge neon sign floating above it saying "Super Secret Daemon Task Force Headquarters" - and simply allow it to continue operating because it poses no threat to them.
- A similar rationale obtains for the enormous set of underground tunnels built by the deep-down dwarfs in Ankh-Morpork in Terry Pratchett's Discworld novels. By digging under the city, they can create their own dwarfs-only authentic dwarf mine under the city, unbeholden to city law or city rents. After the events of the book Thud!, the deep-downers are thoroughly discredited and Lord Vetinari appropriates their delve for the city government. (It is heavily implied that these tunnels will form the basis of a future Ankh-Morpork subway system.)
And the dwarfs have better legal standing than Wonka, considering that on parts of the Disc that dwarfs normally live, such as the Ramtops and Überwald, dwarf-law does cover the underground and is entirely separate from surface law. This just isn't true on the Sto Plains.
The bulk of Dwarf civilization away from Ank-Morpork is also mostly underground. There are huge cities.
- The Illuminati's Bavarian headquarters in Duumvirate is one of these. Parts of it are a couple of centuries old.
- In the Dale Brown novel Fatal Terrain, Taiwan has a secret underground air base.
- Dénis Lindbohm's Frostens barn (Children of the Frost, given the context of the story) features this trope as the home of the surviving remnants of humanity and their descendants, with them living in an increasingly sprawling set of constructions under the Scandinavian Mountains. In story, more installations were supposed to be built... but they were either unfinished or sabotaged when World War III came.
- Center, The Chessmaster AI of The General series located in a warren of abandoned hi-tech tunnels deep beneath East residence. It is unclear whether this ancient HQ was designed to be underground or has been buried by subsistence over the millennia since the Fall.
- The Ministry of Magic in Harry Potter is completely underground that can be reached via elevator telephone booth, flushing down magic toilets (no joke), Apparation or Floo powder.
- Stephenie Meyer's The Host
- The Hunger Games gives us District 13, which is extraordinarily large.
- The sapient rats from Mrs Frisby And The Rats Of NIMH built themselves a Mouse World version of this trope under the farm. No actual Applied Phlebotinum is present by human standards, but by the standards of other animals it's a regular Mad Scientist Laboratory.
- In the NUMA Series, Dirk Pitt has infiltrated his share of these.
- Salamandastron for the Long Patrol, and the Kingdom of Malkariss for one set of baddies, in the Redwall books.
- The Observatory in Septimus Heap is heavily hinted at to be this.
- Supervillain Doctor Impossible of Soon I Will Be Invincible has a base descending deep into the Earth: when he returns to it after his last defeat, the deeper levels are still intact. Also, his first base was dug down from the basement of an ordinary suburban house.
- In Star Trek: The Genesis Wave, the Lomarians (Plant Aliens responsible for unleashing the titular weapon) have one of these. It's justified in that the ecological devastation on Lomar has forced their people underground.
- In Kim Newman's short story "Swellhead", the ghostly remains of the Elaborate Underground Base of a supervillain from an Alternate Universe 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).
- The Thrawn Trilogy has the Mount Tantiss facility on Wayland.
- To a lesser extent, the cloning facility on Dantooine in Galaxy of Fear.
- In the Time Scout series, half the action takes place on time terminal 86, in a winding cavernous complex in the heart of a Tibetan mountain in 1912.
- Superhero School Whateley Academy in the Whateley Universe 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.
- J. R. R. Tolkien was big on these, for good, bad, and ambiguous guys.
- In The Hobbit, you have dwarf Kingdom Under-The-Mountain in the Lonely Mountain (pwned by Smaug the dragon). In The Lord of the Rings you have Khazad-dűm (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 The Children of Húrin.
- Morgoth, the Big Bad of The Silmarillion had Utumno, which amounted to an underground country, plus Angband (whose excavation produced enough refuse and slag to pile into an enormous mountain). Both were filled with vast mines, dungeons, torture chambers, and other... pleasant things.
- Elves vastly prefer to live above-ground, but oddly enough a few groups also built/excavated underground fortress-cities. Underground elves are rather unusual in fiction... perhaps the assumption that Our Elves Are Better means they don't live in holes in the ground anymore. Only 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 Doom: Hell on Earth, the Mormons have built a sprawling bunker complex under Salt Lake City. Lampshaded by Fly when it reminds him of a James Bond movie.
- In Shatter Me Castle creates Omega Point, an underground city where people with gifts gather to plan a rebellion against the oppressive Reestablishment.
- SHADO Headquarters in UFO is located beneath a film studio. Think about it...
- The second season of Space: 1999 saw the command team move from the above-ground "Main Mission" set to a "Command Center" located deep underground.
- Season four of Buffy the Vampire Slayer featured a military organization called The Initiative with a massive high-tech base underneath Sunnydale, where they held demons captive and used them for medical experiments. The Master's lair in season one also fits the trope.
Buffy: You said it was big. You didn't say it was huge.
- In the Doctor Who episode "The Runaway Bride", The Doctor finds an elaborate ex-Torchwood One research facilty beneath the Thames river in London.
- Of course, that's far from the only Doctor Who example. In particular, the 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 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 Hogan's Heroes, the Allied POWs/spies had a network of tunnels under Stalag 13, to which Colonel Klink was consistently oblivious — not the sort of cramped tunnels POWs might dig with spoons, but what you would find in a long-worked industrial mine. How the tunnels had been dug undetected was never explained.
- Lampshaded in one episode in which the grounds have even more snow than usual, and the POWs have built a snowman. At one point, Col. Hogan indicates a particular patch of dirt and claims that it is "the only spot in camp that doesn't have a tunnel under it."
- Most of the Dharma stations on LOST are partially or completely underground, and are of varying complexity. The Pearl and the Orchid are entirely underground. The Orchid is quite elaborate and gives way to an even deeper cave containing the wheel which moves the island.
- Deep 13, from Mystery Science Theater 3000, supposedly. As noted, there is also one in the series finale, in the movie Danger: Diabolik.
- Neil Gaiman's Neverwhere features an entire sub-culture beneath London. There were also undergrounds beneath every major city on Earth, each distinctively dangerous. At least according to Huntress.
- Power Rangers uses this quite often. Some seasons, such as the original, simply imply it, while others are more blatant about it. The fifteenth season, Operation Overdrive, commonly does a cutaway to the base by showing the aboveground mansion, and then dropping the camera via CGI through several layers of planetary crust. For added hijinks, the Rangers in this season are implied to be sliding down kilometer-length fireman poles to reach said base. And on top of that, they have three Humongous Mecha and a Cool Ship hidden inside.
- Super Sentai used this in multiple series. Zyuranger, Ohranger and Go-Busters are prominent examples.
- The Go-Busters base has tunnels that extend to various areas of the city, similar to an anthill, and the Zyurangers' base (located beneath an apartment building) has portals to other dimensions.
- 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.
- Ryukendo has such a base hidden beneath a police station, accessed by praying to the elevator (really). It also serves as a Haunted Headquarters.
- In Stargate SG-1, Stargate Command functions as an Elaborate Underground Base that includes a functioning interplanetary wormhole (see "Real Life" example, below). In later seasons, the "Alpha Site", "Beta Site" and "Gamma Site" are all built as copies of the SGC on other planets.
- The Genii of Stargate Atlantis act like Space Amish while actually living in these. Their true nature gradually becomes one of the worst-kept secrets in galaxy.
- The 60s series The Time Tunnel featured a colossal underground base that housed the titular Time Travel device.
- Torchwood Three in Torchwood is hidden under Roald Dahl Plass, Cardiff. This is in stark contrast to Torchwood One's tower in Doctor Who, which is Canary Wharf. The Torchwood Three base was a deviation from the classic luxurious underground base — aside from the central hub, it was a rat-nest of cramped rooms and converted tunnels that have been repurposed and rebuilt over decades, it was dim and dingy, and water was always leaking in from Tiger Bay. The trope is Lampshaded in Children of Earth.
Rupesh: "What's in there?"
Gwen: "Big...science fiction superbase. Honestly!"
- M.I. 9 has an Elaborate Underground Base concelaed beneath St Hope's School in MI High. Given it houses only three operatives and their handler, it does seem somewhat like overkill.
- The Avengers episode "The Living Dead" had a huge underground city built by the villains for the purpose of raising an army.
- The Dollhouse underneath Los Angeles is pretty much a self-sustaining spa eight stories down.
- Xenon Base in Blake's 7 was an Elaborate Underground Base owned by a Villain of the Week. Upon his death, the heroes moved in and made it their base of operations for the remainder of the season. When you are a marginal band of outlaws facing a star-spanning empire, there is significant psychological comfort of being hidden under megatons of rock.
- Season 4 of Alias introduced APO, a black-ops branch of the CIA (that most of the CIA doesn't know about) located underneath Los Angeles and accessed by the subway.
- 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 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.
- ''JAG: In "Sightings", the abandoned military airfield was built with underground aircraft shelters, being used by drug runners to conceal their operation.
- The titular team in Mutant X has a fairly spacious and comfy facility inside a mountain with a hologram covering the entrance. It looks more like a loft than a secret base.
- In the ninth episode of Strike Back: Project Dawn, Scott and Stonebridge find their way into a system of Cold War-era underground bunkers, which the Big Bad Latif was using as his base. Among the amenities are various storage, manufacture and testing facilities for Weapons Of Mass Destruction, which Latif had used in the development of his VX distribution system. A number of corridors are shown that could fit a tractor-trailer, and satellite scans indicate that the system is about 50 kilometers across and forms a five-point star.
- In Season 8 of Supernatural, Sam and Dean have the Men of Letters' bunker.
- In Helix, isolated research base Arctic Biosystems has several subterranean levels, the depth and extensiveness of which initially jar the CDC team sent to investigate there.
- Gerry Anderson seems quite fond of this one.
- In Joe 90 the BIG RAT was located in a secret underground facility beneath Professor McClaine's house.
- In Stingray (1964), during alerts the entire city of Marineville can descend into a secure underground facility on hydraulic jacks. (Just in case anyone thought Neon Genesis Evangelion did that first...)
- Thunderbirds of course had the Thunderbird hangars beneath Tracy Island.
- Alpha Complex from Paranoia is usually an elaborate underground warren with all the super-science facilities you could ever need. note
- The dwarves of Warhammer live in huge undergound cities, following the example set by J. R. R. Tolkien. And the Skaven live below those in big cities and tunnels that span every continent.
- Warhammer 40,000 gives us the planet of Calth in the Ultramar sector, where this is the only kind of base because the sun is deadly. Necron tomb complexes also qualify.
- Despite the name, virtually none of the "dungeons" in any Dungeons & Dragons campaign are prisons. They're either natural caverns full of unintelligent monsters (rare), tombs full of undead (uncommon), or this trope for the Villain of the Week (extremely common).
Taking this to its logical extreme is Malsheem◊, fortress of Asmodeus, god of sin and tyranny and lord of devils. As the fourth edition has transformed the Nine Hells into a planet, Asmodeus' fortress is comprised of the entire core of that planet.
- The entire raison d'etre of House Telamones, Nosferatu bloodline from Vampire: The Requiem. They build elaborate underground bases to suit the tastes of their undead betters, but woe to the Would-Be Vampire Overlord who accepts the bid from a competing firm... it's mentioned in the text that House Telamones has BLOWN UP an entire CITY BLOCK OF SEATTLE rather than lose a bid.
- The Jadeborn in Exalted, being the game's rough equivalent of dwarves/elves/gnomes, built underground cities, nations, military bases, factories, incomprehensible giant artifacts, and everything else an entire civilization of genius-craftsmen-artificers-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 Tabletop Game/Traveller Adventure 3 Twilight's Peak. A large Ancient base on the planet Fulacin was hidden underground. It was captured by the Zhodani who secretly controlled Fulacin and used by them during the Fifth Frontier War.
- The Black Mesa Research Facility in Half-Life is one of the biggest and most elaborate underground bases ever shown in detail. It is a repurposed top secret rocket research facility from the cold war that has been upgraded to house a massive Teleportation and Inter-Dimensional Travel research project. It has its own hydroelectric power plant, nuclear waste disposal facilities, and a dormitory complex big enough to allow at least the top researchers to have their families living with them, which also requires multiple security checks for all personnel when moving between sectors. Which is usually done by using the local monorail tram network. Some of the largest and longest levels of the game and its add-ons take place in the Freight Yard, which consists of a large number of warehouses and its own container terminal to unload the 40-feet-containers that arrive by train. The fact that outdoor environments look just awful in the old Quake engine may have had more than a bit to do with the base ending up mostly underground. The few outdoor levels that exist consist entirely of brown rocks and concrete walls.
- In the end it takes an underground nuclear bomb to eliminate any remaining witnessess and all alien forces still inside the facility. Though that event might be non-canon and is neither mentioned by the games from the main series developers, nor does it fit with the details revealed in later games.
- It also is probably no coincidence that the Black Mesa Research Facility is located in New Mexico, putting it in the general region of the real world Los Alamos National Laboratory (atomic bomb), Edwards Air Force Base, Arizona or "Area 51" (experimental jet-aircraft), and Black Mesa Test Range, Utah (ballistic missiles).
- The whole of Breath of Fire V takes place in a geofront like super cave.
- A few games have appeared where constructing an Elaborate Underground Base is a major aspect of the gameplay, notably:
- Bioshock takes place in a underwater city/base named Rapture, where Applied Phlebotinum is developed, refined, and horribly goes wrong - the player's stated goal is to get out alive.
- City of Heroes features this to an almost ridiculous extent. The Cobra-wannabe Council (formerly the Fifth Column) generally base themselves in converted caves, as do the Rikti, and even the evil cultist Circle of Thorns have their ancient underground city. The Faultline zone (former Scrappy Level Rescued from the Scrappy Heap) is said to be filled with former superhero bases that were abandoned in the earthquake that gave the zone its name, and people are trying to dig them up...
- Not to mention the Shadow Shard - an alternate dimension seemingly comprised entirely of floating islands in the sky, with caves and bases dug into them anyway. If the game world had a consistent geometry, it'd likely resemble a very big ant hill with more empty space than rock.
- Pokémon Red and Blue and Gold and Silver and their remakes have the Team Rocket bases, which is actually pretty elaborate considering they tend to build them under game corners and converted ninja bases.
- The Spin-Off games Pokémon Colosseum and Pokémon XD: Gale of Darkness had the Cipher Lab, which was rather complex. The only thing is, there was one floor on the upper level that was actually important for getting through the base (the button needed to unlock the door was there), so it can't be considered a true base.
- As well as the first Pokémon Ranger, where the Go-Rock Squad's base is underground in a mountain.
- It continues in Pokémon Ruby and Sapphire and Emerald, with the Team Aqua and Magma bases; in the former two, the antagonistic team's base is hidden in a seaside cave near Lilycove City, while in Emerald, Team Aqua takes the cave and Team Magma has a base inside the Hoenn region's active volcano, Mt. Chimney.
- Pokémon X and Y has one Team Flare base under Lysandre Cafe and one underground at Geosenge Town.
- The No One Lives Forever series had a couple. The first game had one in the US Pacific Northwest and an underground rocket launch facility somewhere in the South Pacific. The 2nd had an underwater base you had to infiltrate.
- In the Command & Conquer series, nearly all of the Brotherhood of Nod's military facilities have some kind of extensive underground component. For example, the Hand of Nod has a massive training and fitness area, as well as a mock-up forest environment for combat practice, and an interrogation cellar.
- Expanding on that, in Command & Conquer: Red Alert, there were the beautiful and famed internal missions. With computer consoles that actually did things.
- From the Fallout RPGs, the various Vaults.
- Fallout 1 had the Glow, the Mariposa Military Base and the Brotherhood's Lost Hills HQ.
- Fallout 2 had the Sierra Army Depot and the Hubologist base. The Brotherhood bunkers in the Den, NCR and San Francisco might also count.
- Fallout 3 had Raven Rock and the Rockland comm. facility.
- Fallout Tactics had the Brotherhood bunkers and Vault 0 which was simply the Cheyenne Mountain Complex coverted into an even larger facility.
- Fallout: New Vegas has several: the Brotherhood, as usual, lives in an underground bunker, the Enclave remnants keep their Powered Armor and vertibird in one, and Mr. House has a Mecha-Mooks factory built under Fortification Hill. The Big MT Research and Development Center from Old World Blues used to be one (back when it was, you know, a mountain), but then the Mad Scientists there blew the top off of it.
- F.E.A.R.'s Armacham Technology Corporation established the main facility for the Origin Project in an old military-industrial complex, and built the entire facility deep underground. Emphasis placed on the past tense, what with the explosive ending of the first game.
- Project Origin takes it even further. The Auburn Memorial Hospital is a full-sized building constructed underground inside another Elaborate Underground Base. Wade Elementary has another Elaborate Underground Base beneath it. And that's before you get to the giant tram tunnels running through titanic chambers that include a Replica storage facility and massive maintenance area. Pretty much the entirety of Fairport is riddled with Armacham secret bases.
- One wonders how nobody found out about it or that all the excavations didn't fatally weaken the ground.
- Final Fantasy V had the Catapult, an underground/underwater base of Lost Technology. Among other things, it features an airship docking bay, a teleporter and a ship-sized elevator to the sea surface. And the icing on the cake? It's yours now.
- The Aperture Science Enrichment Center in Portal is located, per the supplementary material, in an abandoned salt mine in Cleveland, Ohio. Portal 2 bizarrely retcons this to be in 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 entirity of Over Blood takes place in one.
- Gears of War features the hollow, which is home to the entire Locust civilization. It runs all throughout the planet and there are areas inside of it big enough to have skyscrapers and air patrols.
- Every single Forerunner Halo installation in the Halo universe is built underground. Presumably, this is so that experiments could be performed on the surface, while the Forerunners would stay underground to monitor the results.
- Halo 3 - the second level takes place in Crow's Nest, an "old 20th century" military base inside Mount Kilimanjaro, which has been re-activated after the Covenant took over Earth. This base comes fully equipped with a hangar bay, hidden landing pads, big imposing steel doors and a war room, complete with big screens and Bridge Bunnies.
- Metro2033 features the entire subway system of Moscow, which is home to the remnants of civilization. It also features huge military installations even below that.
- In Resident Evil, seemingly every building in Raccoon City, or in the forests surrounding it, has at least one well hidden elevator leading into one of the multiple underground Umbrella Corporation labs (which makes sense when you consider that Umbrella essentially owns and runs the city).
- The British army in Resistance: Fall of Man has two underground bases from which they were staging their attacks on the Chimera. Extra content reveals that they had a third underground base, but it was flooded by the Chimera before the start of the game.
- Skies of Arcadia has elaborate underground bases for both the heroes and the villains.
- In World of Warcraft, 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 Thief II: The Metal Age, the Cetus Project is run from Markham's Isle, a former pirate base taken over by the Mechanists. As you learn when you go there, the administration of the project is a bit complicated, but Markham's Isle certainly fits the Island Base and Elaborate Underground Base tropes.
- The X-Com franchise. All of the X-Com bases (situated and built, room by room, by the player) were only accessible through the main elevator and the vehicle hangars, which affected gameplay if the aliens located said bases and attacked them with a relatively manageable number of alien foot-soldiers.
- Same goes for Alien Bases, including the main base at Cydonia. Crosses over with Underwater Base in the case of the Colonies and Artifact Sites from Terror From the Deep, which are underground installations built on the ocean floor.
- The Firaxis remake enhances base-building by allowing you to determine where to dig, 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.
- Deus Ex concludes in Bob Page's base beneath Area 51. On the good side, Tracer Tong has a sophisticated laboratory several floors beneath his Triad's compound.
- The Elder Scrolls III: Morrowind had a pretty large numbers of natural caves, often inhabited by smugglers. Most were small, like 2 or 3 rooms furnished with hammocks, candles and crates, but some other were kind of large, hosting a whole guild and richly decorated and furnished.
- In Oblivion you can get one for yourself via the Thieves Den DLC. It is pirate-themed and has once taken over you can recruit pirates to give services(like skill-training and selling stuff like lockpicks) and go out stealing for your benefit.
- The area under the Optimology building in 6 days a Sacrifice counts.
- In Gaberial Knight:Sins of the Fathers, the Voodoo Cartel has one Under Jackson Square. God knows how they managed to put that in without anyone noticing.
- In the first Mega Man Zero game, the La Résistance's base is located underneath an abandoned city. While the "base" itself is run-down, there 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 Mega Man X7.
- Most Space Pirate bases in Metroid games tend to be these. Probably because both their homeworld and their main base at Zebes are plagued by near-constant acid rain.
- Shadow Complex is a Metroidvania game that takes place in one gigantic base.
- Naoto's dungeon in Persona 4 is one of these.
- The Alpha Protocol base in, well, Alpha Protocol is a large underground complex apparently located somewhere in the American northwest. Reaching it is pretty difficult; agents are sedated into unconsciousness and transported to the location, via aircraft and boat in order to keep the base's location secret. At least until the endgame, where Mike arranges for his allies to track him while he's being sedated and ruin everyone's whole week with a surprise assault.
- Colossal Cave, including the maze of twisty little passages, all alike.
- The Zork games take this to an extreme, what with most of the games taking place mostly in the Great Underground Empire.
- Fort Schmerzen in Medal of Honor 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.
- In Metal Gear and Metal Gear Solid, the titular Humongous Mecha is hidden in one of these.
- Metal Gear 2 has a variation: Although Metal Gear D is fought in the third (sixth?) basement floor of the main building of Zanzibar Land's detention center, it is not specified if it was actually the main hangar for Metal Gear D. Similarly, the Big Shell is technically above ground (or in this case, above water), but it is disguised so well as a cleanup facility that the personnel could literally get away with having armed forces stationed there as well as developing Arsenal Gear without the populace ever suspecting anything.
- This seems to be fusing metal gear two, and metal gear solid two.
- In Metal Gear Solid: Portable Ops, there are three elaborate underground bases: One is the Nuclear Storage Facility (which is the deepest mapped area of the game), another is the Silo Complex (which is pretty deep underground, although the mapped areas themselves are actually shallower than the Nuclear Storage Facility), and it was originally intended in-game to have more than one missile silo. The last one isn't actually visited by the Player: It is the underground bunker underneath Langley that the CIA director attempted to retreat under with the impending nuclear strike against America with his half of the Legacy, and where Ocelot essentially murdered him and made it look like he committed suicide.
- In Metal Gear Solid: Peace Walker, both the heroes and the villains have elaborate bases: The Peace Sentinels had an AI Weapon assembly plant situated within a pumped storage hydroelectric power plant within Irazu's crater, an AI programming lab constructed either within an unknown ruin or an AI lab disguised as a ruin (Paz's description of the plant makes the ruin's exact origin a bit ambiguous), and an AI Weapons forwarding/Peace Walker construction base built within a gold quarry. In addition, the FSLN / KGB's drug facilities were also disguised as Banana and Coffee processing factories, and the Militaires Sans Frontieres also utilized an elaborate base in the form of an off-shore OTEC research facility.
- The Ancients in (old verse) Might and Magic seems to have been fond of placing large facilities underground. The inhabitants of Deyja went one step beyond and built themselves an Elaborate Underground City.
- In Grand Theft Auto: San Andreas, Carl must infiltrate one of these under a base called Area 69. Yes, it's inspired by Area 51 (see below).
- Saints Row 2 features a base called The Pyramid hidden under a mountain. Amazingly, the company that built it was a clothing company in the first game set five years earlier.
- The Saints themselves have their headquarters in an abandoned hotel that collapsed below street level after an earthquake many years previously. Eventually, it is renovated into a sumptuous, neon-lit, subterranean nightclub called "Purgatory."
- In Sid Meiers Alien Crossfire, the Human Hive faction's bases (equivalent to cities in Civilization) are stated in the fluff to be of the underground kind.
- In Win Back, the GULF control center is hidden beneath a factory and office building.
- The Russian missile base in the last act of Modern Warfare, which is also Ye Olde Nuclear Silo.
- The moonbase setting of BioForge, complete with hangar bay, cryogenics lab, prison, defense tower, medical experimentation lab.
- The majority of Still Life 2 is set in an unassuming house in the woods. The house is substantially larger than it appears due to the expanded atomic shelter underneath.
- In Narbonic, Narbonics Labs moved to an underground lair early in the strip's run. Later subverted when Madblood brags to Helen about his underground lair; when she and Mell come to visit, they find him living in his mother's basement.
- Seems to be the basic design for all Orsintos laboratories in Sluggy Freelance. Surprisingly, there's been nothing so far to suggest that Hereti-Corp has one of these.
- As it turns out, Dr. Steve's Baselab was designed to burrow underground.
- The main characters of The Pocalypse have a base placed under a supermarket in a city.
- Times Like This: It may technically be an Elaborate Underground Base, since it's run by a multination secret-service consortium, but Paratopia is actually an underground Club Med-type getaway roughly the size of Delaware.
- In S.S.D.D Cook has one that was originally a partially completed nuclear storage dump under his corporate headquarters, which he uses for R&D clean rooms, officially. In reality he and the other time travelers trying to prevent the coming Anarchist revolution hide all their future stuff down there. Tessa suspects he might be turning into a supervillain and uses the underground as evidence.
- In the Global Guardians PBEM Universe, most of the Evil Overlords and Diabolical Masterminds have one of these. The most notable example might be 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.
- Pelvanida from Darwin's Soldiers is an underground military research base. It is not really "hidden" per se, though as quite a bit of above ground infrastructure is present.
- In Teen Titans, multiple villains have one of these over the course of the series, from Slade (at least twice), the HIVE Academy run by Brother Blood, and the final base of the Brotherhood of Evil.
- The Tracy Island of Thunderbirds could well be the Trope Codifier.
- In a series full of Supervillain Lairs to begin with, in the Birdman episode ("Number One") that brought them into the open and really defined them as a threat, F.E.A.R. turned out to have an elaborate underground base.
- In the Chip 'n Dale Rescue Rangers pilot, Aldrin Klordane had turned a cave conveniently placed underneath the Federal Gold Reserve into his own Elaborate Underground Base which not only has a diagonal monorail, but even a real railroad connection.
- Dangermouse lived in an underground base in postbox on Baker Street in London, the same road as Sherlock Holmes.
- Vlad built himself one in Danny Phantom by the beginning of Season Three. Through an alternate universe, the underground base was a Foreshadowing element in a previous episode. Too bad he didn't find the time to put it to good use.
- Dexter's Laboratory, though how underground the lab is isn't really gone into, mostly due to physical impossibility.
- Gummi Glen in Gummi Bears. 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 The Incredibles, 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!
- Jackie Chan Adventures had the underground base of Section 13 in San Francisco. Said organization was where the main characters would live along with being the location of what ever MacGuffins were being collected that season. Could be reached via a phonebooth elevator or "the stairs".
- Global Justice headquarters, and several of Drakken's lairs, in Kim Possible, which also has a twist on the trope: Frugal Lucre's lair in his mom's basement.
- Also, a few of the locations that Drakken raids are themselves underground bases. Case in point, the episode where he steals some HypnoTrinkets had him raiding a base in the Cold Opening that was built underneath a desert, and a conspicuous cactus acted as a card key scanning device to grant entry.
- The Road Rovers had an Elaborate Underground Base. It was strongly implied in at least one episode that it was the remains of a lab in Socorro, NM, that the Rovers' mentor ran.
- The SWAT Kats have a base hidden beneath the Cool Garage where they live and work.
- The Teenage Mutant Ninja Turtles live in a hideout within the sewers of New York City.
- Don't forget about the Labyrinth in Gargoyles.
- Or the base Hacker dug out for himself in an episode of Cyberchase. He abandoned it by the next episode, though.
- Jonny Quest TOS episodes "The Dreadful Doll" (arms and submarine base being built on the island), "Pirates From Below" (cave system with submarines and hovercraft), "The Fraudulent Volcano" (built under/in the title volcano).
- In The Simpsons, 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.
- Avatar: The Last Airbender . The Dai Li had a undergound base under a lake.
- Perry The Platypus has one underneath Phineas and Ferb's house, and the rest of the OWCA base seems to run beneath all of the Tri-State area. All of it.
- Hedgequarters from The Mysteries Of Alfred Hedgehog is a benign junior version of this trope.
- Super Friends 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.
- Underground command-and-control centers started getting popular sometime after World War I, and much more so after nuclear weapons and ICBMs. Greenbrier Resort was the site of a US Congressional command center for 30 years, until a Washington Post reporter exposed its existence in 1992. Cheyenne Mountain, Colorado, is quite famous as the "brain" of NORAD (NORth-american Air Defense), SAC (Strategic Air Command, bombers and land-based ICBMs) and the US Space Command (more to do with satellites, though). The latter two are now defunct, absorbed into other 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 Situation Room (yes, it really does exist) underneath the West Wing of the White House. Yes, this is where the President and his cabinet meet to make life-or-death decisions. No, it is not full of beeping computers.
- Russia, ex-Soviet Union, undoubtedly has its own, but locations are disputed.
- There's supposedly an entire secret subway system under Moscow, bigger than the regular one and buried up to 200m underground, linking numerous important buildings and providing means for movement and evacuation of VIPs.
- Nobody in the West seems to know what's under Mount Yamantau, but whatever it is, it's definitely huge.
- Similar to the Greenbrier Resort are the Canadian Diefenbunkers
- A few shots in the movie WarGames showed the actual Cheyenne Mountain complex. The NORAD room in that was a mock-up (the most expensive movie set ever at that time) and far more snazzy than the real one. This was due to the 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 Stargate SG-1 and Jeremiah (This one has the benefit of being a real complex). In the original movie Stargate, the Gate was hidden in the fictional Creek Mountain complex — also in Colorado, and to boot having recycled the Cheyenne Mountain entrance set from WarGames. The series retconned the Stargate's location without much fuss.
- Raven Rock, most famous to gamers from Fallout 3, is a real base built for much the same purpose as Cheyenne Mountain.
- Offutt Air Force Base is rumored to have an underground command center proof against anything short of a direct hit with a nuke. It's impossible to be certain, because those chambers are not on the Official Elementary School Field Trip tour, they're still in use. (George W. Bush did not fly to Omaha on 9/11 because he wanted steak for lunch ....)
- After the Cold War, the Strategic Air Command bunker in Amherst, Massachusetts was put up for sale. Who besides the government could want an elaborate concrete bunker? Librarians, apparently; the Five Colleges bought it for cheap, and now use it for book storage. The low temperatures and lack of sunlight are ideal for preservation, and it's hard to beat the security.
- Speaking of decommissioned bunkers and missile silos, there's a real estate company specialising in such properties.
- After the First World War, the French built the Maginot Line on their border with Germany, a chain of defensive fortifications, most of which are underground, connected by underground tunnels with bunkers and living facilities. It was an amazing feat of construction. And ever after, people have caricatured it by pointing out that the Germans went around it—which is true but misleading, because that was the purpose of the Maginot Line.
- Visitors to Eastern France intending to check out the Maginot Line are strongly advised that not all of it has been decommissioned and made redundant. Far from being a historical relic, many parts of the Maginot installations are still in use today by parts of the French armed forces who do not welcome casual visitors, such as the special forces and the nuclear weapons defence establishment.
- With the end of the Cold War, only one part of the Maginot Line remains in use as of today (2014). It is the Ouvrage Hochwald, one of the larger fortresses on the Line, currently used as a hardened underground command center by the French Air Force.
- For contrast, Britain had Kelvedon Hatch Nuclear Bunker, a base for the nation's power structure hidden beneath a nondescript house. Apparently, it was active until 1992 (but only ever activated once: not for a nuclear crisis but for the poll tax riots). This site has pictures of it. It's now a tourist attraction and the real command centre is somewhere secret.
- Has been used as a filming location.
- London also had Churchill's Cabinet War Rooms under the Treasury building. Their existence was kept a secret until the 1980s, when they were renovated and opened as a museum.
- Switzerland has built and maintained an extensive system of fortifications, tunnels, living facilities, and storage facilities, much of it underground or at least dug deep into mountains, called the National Redoubt, dating back to late 19th century. In the 20th century, they enhanced it such additions as underground/in-mountain hangers 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.
- Iran is currently trying to protect their nuclear program by having the dedicated facilities be hidden in a series of tunnels, making it significantly more complicated for anyone to bomb their reactors and centrifuges.
- 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 Crazy Awesome 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 Berkeley's central Doe Memorial Library take up about three stories below Memorial Glade (complete with skylights that are at ground level above).
- This is a common strategy for large university libraries - Firestone Library at Princeton University has three underground stories (all much larger than the above-ground footprint) housing more than 70 miles of shelves.
- The Cu Chi Tunnels in Vietnam are another great example, and are almost the archetype of the EUB.
- The term "undisclosed location" entered the public lexicon after US VP Dick Cheney was stated to be touring them after attacks on DC and New York. Because of his reputation, it is somewhat assumed that any use of the term implies this trope played to the hilt.
- Conspiracy Theorists speculate about the existence of DUMB, or Deep Underground Military Base. It doesn't sound any more sinister than your regular well-protected military base, except that it's supposedly run by your favorite conspiracy (The Illuminati and The Reptilians 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.
- Julian Assange's Wikileaks facility in Stockholm.
- It's just a web host. It doesn't belong to Assange.
- It happens in private as well. In 2005, Fred Strunk was sentenced to 18 years for running an elaborate pot growing operation in a cave in Tennessee.
- This datacentre in Sweden, located in a cold war era nuclear bunker.
- In London, the underground railway linking Royal Mail facilities, now closed, but documented by urban explorers.
- The North Korean military has a lot of bases created underground, some hollowed out from mountains to protect their equipment from bombardment in a future conflict involving South Korean and American bombing raids. The North Korean military also had several underground tunnels built so their troops could surprise-invade South Korea when the time is right.
- 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 hangers and Air Force bases but nothing truly out of the ordinary, this had led people to believe that there must be something underground they are hiding if the surface appears to be normal.
- The Magic Kingdom at Walt Disney World famously has the utilidor system, a series of underground corridors in a ring around the park (plus a central corridor) that includes virtually all of the important employee areas and allows them to quickly move to any area of the park without being seen by guests in the wrong costume. Ironically, the utilidor technically isn't underground; Florida notoriously has a very high water table that makes it excessively difficult to build anything below ground, so the Magic Kingdom is actually built on a raised hill (made from the earth scooped out for the Seven Seas Lagoon) with the utilidor built at ground level.
- Humans don't have a monopoly on this trope either; ants have been known to form some fantastically complex underground structures. You think this one is impressive then the largest one know, under Hokkaidō, has an area of roughly 2.7 square kilometers.
- Allegedly, Osama bin Laden's "command centre" in the caves of Tora Bora mountain was this, with reports of fully equipped hospitals, hydro-electric power stations, a hotel, a tank park, and facilities for 2000 men flying around prior to its capture by NATO forces during Operation Enduring Freedom. Turns out it was a system of natural caves, with a few small manmade connecting tunnels, housing for 200 men at most, some middlingly sized ammunition depots, and rudimentary medical facilities run by The Dragon (Ayman al-Zahawiri is a qualified surgeon). Whilst possibly more impressive than usual guerilla hideouts, it hardly lived up to its hype.
- The Large Hadron Collider in Switzerland certainly lives up to its name - at a depth of 175 meters with a circumference of 17 kilometers, it is both astoundingly large and astoundingly elaborate.
- Much of the German-built Atlantic Wall was built underground. Several sections have been restored for tourists but even those that have been left to rot are often in good enough shape to visit.
- A non-military example is the Leas Cliffe Hall in Folkestone, Kent, a 700-seater theatre/performance venue and conference 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 WW2, and its underground structure was greatly added to so as to protect it from German bombing and long-range artillery.
- The Matshuhiro Underground Imperial Headquarters near Nagano was intended to be this for Imperial Japan as the Allies turned the tide of World War II - since Tokyo was on the coast, it would have been too risky to leave the central apparatus of the Japanese government there in the event of a US invasion. Construction began in November 1944 and it was about 75% complete when Japan surrendered the following August.
- 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.