Going Deep
An Overview of the Underground

FORMER LIMESTONE MINE CAVERNS MAY be the largest redeveloped and occupied subterranean structures in the nation, but there are other kinds of mines and underground spaces all over the place, some of which have been redeveloped in curious ways too. There is also, of course, intentionally constructed occupy-able underground space, like basements, vaults, and tunnels. One wonders at times if there may not be more enclosed space below the surface of the nation, than above it.  

In cities, lots of  space can be found underground. Most tall buildings extend below grade, and sometimes these spaces are connected to shopping malls, subway stations, pedestrian tunnels, and parking garages, all below street level. This subterranean city can be an interconnected public space, where people might not even be aware they are underground, or care. It is simply an extension of the city below grade, without streets to cross, or weather to endure. Street level itself is a mutable thing in cities, as exemplified in places like Seattle’s or Atlanta’s downtown, where storefronts from older street levels can be visited on underground tours.

Outside of cities, corporate, industrial, and educational campuses, with integrated buildings on a limited footprint, are rife with underground spaces, like the steam tunnels clandestinely explored by collegiate rite and ritual. On campus and off, a remarkable number of libraries have extensive basements, or additions that are below grade. As do other collecting entities, like archives, museums, and government agencies. And most domestic structures have some kind of basement, perhaps with the furnace, or an apartment building laundry room, or perhaps just enough crawlspace inside the foundation to crawl.

In all these cases, these spaces are extensions of the above ground architecture. They are not really, self-consciously, or exclusively, underground. True underground space is space that acknowledges its undergroundness, or requires it. It has some kind of transition, a displacement, between above, and below, the outer worlds and the inner, a portal with a garage door, a ramp, or a 16-ton blast door.

The CLUI has had its head in the ground since the beginning of its existence, understanding that everything on the land has some relationship with what’s below. What follows here is an exploration of true underground spaces, arranged typologically, as they occur across the American land. These sites and more can also be found, in a sense, in our Land Use Database, visitable remotely, if not actually. They are of course all out there, somewhere.

Underground Mines Turned Into Farms, Night Clubs, Data Centers, Physics Labs, and Paintball Fields
Our exhibit about limestone mines that were turned into business parks had to leave out some limestone mines that were turned into other things, things that were not business parks. These include single-purpose businesses, like Toys Underground Storage, a vehicle (primarily an RV and boat) storage company, which uses an old limestone mine in western Pennsylvania. It is near the Creekside Mushroom Farm, which operates inside a former limestone mine as well.

5067 Entrance to Creekside Mushroom Farm, said to be the largest mushroom farm in the country, underground or not. It is inside a former limestone mine, more than a square mile in size, with 150 miles of galleries along its grid of roads. It can produce up to 60 million pounds of mushrooms annually, and employs more than 500 people. Founded in 1937, it is also known as Moonlight Mushrooms, its brand name. CLUI photoIt’s not just limestone mines that get repurposed, of course, though they are the largest kind of underground mine that offers a drive-thru, single layer that makes them convenient for redeveloping. Though generally softer and less stable, and mined in open pits, some former gypsum and sandstone mines have also been repurposed.

A former underground gypsum mine in Grand Rapids, Michigan was converted into a produce storage warehouse in 1957, called Michigan Natural Storage, though, of course, a mine is not very “natural.” Its caverns are accessed by elevators operating inside two vertical shafts. Around 750,000 square feet is said to be available for use still, underground. In 2001, the Underground Secure Data Center Operations company (USDCO) opened a data center in the mine.

In Crystal City, Missouri, a former underground sand mine has been turned into a recreational center called Crystal City Caverns, with laser tag, volleyball, disc golf, and kayaking tours on a 150 acre subterranean lake. It also has some underground warehousing, though the entire facility has been closed down for a few years due to flooding.

It’s not unusual for recreational activities to be installed inside closed mines. There are zip lines and mountain biking courses in Mega Caverns, in Kentucky, and at SubTropolis, in Kansas City, where Jaeger’s Paintball is inside one of the cavern areas.

The Wabasha Street Caves are former sandstone mines on the shore of the Mississippi River, near St. Paul, Minnesota, which were turned into a speakeasy in the 1920s, and have since been further developed into an event venue and a big band dance hall. A castle-style front was constructed in the 1930’s, when it was known as Castle Royale.

A former underground sandstone mine in Festus, Missouri, was turned into a roller rink and night club called Caveland, where musical acts including MC5 and Bob Seger once played (though not at the same time, unfortunately). It closed in 1985, and sat idle until 2003, when it was bought on Ebay in 2003, and turned into a private home. It is located down the street from Festus RV and Boat Storage (inside another mine, in the same bluff).

Some former mines have been turned into physics research facilities, like portions of the Soudan Iron Mine, in Michigan, which has the MINOS neutrino detector installed deep in the mine, measuring neutrinos sent through the ground from the Fermi Lab, outside Chicago, hundreds of miles away.

The Sanford Lab in the former Homestake mine, in Lead, South Dakota, is another particle physics lab inside a mine. The underground mine is huge, sometimes referred to as the largest mine in the western hemisphere. Over 125 years, more than 40 million ounces of gold was extracted from the mine, until it closed in 2001. There are 370 miles of tunnels, as deep as 8,000 feet down. With private and public funding, the mines have been turned into research for cosmic radiation, like dark matter and nutrinos, which are more visible deep underground, due to the filtering effects of the earth above them.

Part of a decommissioned copper mine in White Pine, Michigan, has been converted by Prairie Plant Systems into an underground grow house and plant research facility called SubTerra. Doing this kind of research in an underground facility isolates it from the outdoor environment, limiting the possibility of contamination from inside to outside, or outside to inside, both important, especially if working on genetic modifications.

Mining in large underground salt deposits occurs in upstate New York, Louisiana, Oklahoma, and underneath the city of Detroit, to name a few places. It creates large hollowed out underground spaces. In a few cases these mines have been turned into storage facilities. The most developed of them is the salt mine in Hutchison, Kansas, one of the largest salt mines in the world, part of which has been turned into a storage site for records and other assets, including Hollywood films and oil company data. Developed by Underground Vaults and Storage, it opened in 1959, when a lease was struck with the Carey Salt Mine, which still operates at the location, under a different name. Underground Vaults and Storage (UV&S) has expanded into several other cities, though it has underground locations at only two other sites, in Mega Caverns, in Louisville, and in the SubTropolis development in Kansas City, where it has a refrigerated film vault.

5068 A storage area for Underground Vaults and Storage is part of the display of the Salt Mine Museum. The two entities seem to be merged underground. CLUI photoAt Hutchison, UV&S has 1,660,000 square feet of storage space, employing 65 workers, within a mine that covers more than a square mile underground. The mine has a vertical entrance only, and is not a drive-in cavern, like many of the limestone mines that have been converted into storage. In 1985, UV&S built a loading dock building next to the shaft that connects to the mine. In 2003, the Kansas Underground Salt Mine Museum was established, operated by the county historical society and supported by the salt company and UV&S. A new shaft into the mine was constructed, and opened in 2005. Visitors descend in the main shaft, 650 feet below grade, and can tour 100,000 square feet of the mine filled with displays, next to the UV&S storage location.

Iron Mine Turned into Iron Mountain
After a series of acquisitions and mergers over the past twenty years, Boston-based Iron Mountain has become the nation’s largest records management and data storage company. Most of its hundreds of facilities around the USA are above ground offices, truck depots, and warehouses, but several are underground. The largest of the company’s underground sites is the former US Steel limestone mine in Boyers, Pennsylvania, which has one of the company’s ten data centers inside it too. But it all started with a former iron mine in Livingston, New York, where ore was extracted to feed the iron works up river at Troy.

5069 Entrance to Iron Mountain, Livingston. This former iron mine, in the Hudson Valley, near Livingston, New York, is where the Iron Mountain company started, and where it got its name. CLUI photoThe surface property at Livingston, which included the now abandoned iron mine, was eventually acquired by a mushroom farmer named Herman Knaust, who marketed the mine as a safe underground storage site for New York City banks and corporations, starting in 1951. Customers were found, initially banks seeking safe records storage, after he set up a sales office in the Empire State Building, calling the business Iron Mountain Atomic Storage. Soon the company expanded into another underground mine, a former limestone mine across the Hudson in Rosendale. The company opened above ground storage warehouses in the 1970s, and started buying up other records management companies, like Bekins, Bell and Howell, and Recall, to become the dominant player in the field today.

Banking Bunkers and other Purpose-Built Underground Storage Spaces
The use of underground space for storage and safekeeping is, of course not limited to re-used pre-existing mines. Purpose-built underground archives and records storage facilities, made during the Cold War and to the present day, are scattered here and there, with a remarkable number around New England.

Iron Mountain expanded into New England in 1980, when it purchased a bank records bunker near Greenville, Rhode Island, known as the Industrial National Bank Repository (a bank that evolved into the Fleet Bank of Boston). The facility was constructed underground for safety and security, in the 1960s, and remains in use by Iron Mountain.

The Pepperell Underground Records Storage Center, in Pepperell, Massachusetts, near the New Hampshire state line, was a vault belonging to the First National Bank of Boston, built in 1960. It was shared with seven other of the major banks of New England. Underground space measures 60 x 120 feet, a total of 7,200 square feet. Known as Location X, it had emergency supplies for up to 50 people, as well as decontamination showers, a generator, and a 16,000 pound blast door. It was located on a 40-acre estate that was also owned by the bank. In 1991, it was bought by Archive Storage Inc, for use as a computer records storage facility. It has been on the market relatively recently.

Off-site underground bank vaults built during the Cold War are not uncommon, though few are in use as records storage vaults now. There is another underground banking bunker in rural northern Connecticut, similar to the vault in Pepperell, though a bit larger, at 10,000 square feet. It was built in 1962 by the Underground Record Protection Cooperative Trust, a group of banks and insurance companies. Its primary function was to store records out of the way of nuclear attack (outside the city, and underground), but, like Pepperell, it could also house a few dozen people, presumably executives associated with the Trust, for a few weeks, and had decontamination showers, cots, and food rations. After its original purpose ended, somewhere in the early 1990s, the bunker changed hands a few times, then fell into disuse. In 2013, it opened as a secure wine storage facility called Horse Ridge Cellars.

One of the most notorious banking bunkers is the former Federal Reserve facility at Mount Pony, near Culpeper, Virginia, a three-level underground vault built by the Federal Reserve and the Treasury Department in 1969 to house the hub of their nationwide communications network, and to store $241 billion in cash (including rows of palletized $2 bills), which would be used to jump start the economy following a nuclear attack. After being offered for sale in the early 1990s, the facility was purchased by philanthropist and film preservationist David W. Packard, and thoroughly redeveloped over many years into the National Audio Visual Conservation Center of the Library of Congress. Inside are millions of movies, TV episodes, and audio recordings on every conceivable recording format, including nitrate film, kept in one of the two underground film vaults there. (This facility was described extensively in the 2013 issue of the Lay of the Land.)

5070 The top of the underground vaults at the Packard’s National Audio Visual Conservation Center, in the former bank bunker at Culpeper, Virginia. CLUI photoThrough the Packard Humanities Institute, which provided the funding for the $250 million facility in Culpeper, David W. Packard built another preservation campus and film vault on the west coast, north of Los Angeles. The facility, next to Interstate 5 in Santa Clarita, opened in 2014, and, from the outside resembles the colonnaded stoa found in the cities of ancient Greece. The interior is modeled after a 15th century Florentine monastery. Two film vaults are located in an adjacent structure, partially underground. Underground storage is considered optimal for film storage, especially the old nitrate films which are unstable and prone to combustion.

There are only a few film archives in the country that store nitrate film, and they include the major film archives in the nation: the two Packard archives; the George Eastman House’s Louis B. Mayer Conservation Center in Chili, New York; and the Museum of Modern Art Film Archive, in Hamlin, Pennsylvania. MoMA’s collection is the largest private film collection in the world. Most of it is located in a purpose built 33,000 square foot, two-building, partially underground compound on 37 acres of woodland and meadows in the Pocono Mountains.

A considerable part of the history of document management and archiving centered around another film medium, microfilm, which was first developed to more efficiently record and store documents by the banking industry in the 1920s. Kodak bought these technologies and expanded them into a standard for archiving newspaper, paper which degraded quickly. As printed information in all forms continued to test the storage limits of archives and libraries, microfilm became the standard master format for much of the printed material produced in the world. Library basements and off-site library storage areas are often full of microfilm, though it is going away—being digitized, like everything else.

One of the largest collections of microfilmed records is inside the Granite Mountain Records Vault, the principal storage facility for the genealogical research programs of the Mormon Church. Since the Mormons are interested in converting the ancestors of every living person, that means having the names for everyone who has ever lived on the planet, or as close to it as they can get. This effort has created the largest genealogical reference system in the world, the hard copy of which is stored on millions of rolls of microfilm (and microfiche) inside this facility—billions of tiny images on acetate. The Granite Mountain Records Vault was constructed in the early 1960s, and contains six archival storage areas, covering a total of 65,000 square feet. The space was created by drilling and blasting into solid quartz monzonite rock at the base of the Wasatch Mountains, in Little Cottonwood Canyon, minutes from Salt Lake City.

Two miles further up Little Cottonwood Canyon from the famous Mormon records vault is another underground storage facility, which is privately owned and operated by Perpetual Storage Incorporated. It was built after the Mormon vault, in 1968, taking advantage of the same monolithic and moisture-free rock structure, and is marketed as a highly secure storage facility. It accepts only digital media, like hard drives, magnetic tape, and optical discs, or microfilm, but not paper, further adding to its non-flammable safety.  

Keeping Good Company: Corporate Bunkers
The extent and location of corporate “go-to” “bug-out” places is one of the most unsolved mysteries of the underground, as it’s hard to tell the difference between something that is successfully hidden from the public, and something that doesn’t exist. But it is certain that it isn’t just the government and banks that had Cold War bunkers for their executives.

One “outed” corporate bunker that received some media attention is the Westland Bunker, located northwest of Houston. It was originally constructed by the owner of Westland Oil, which was headquartered in an office building next door. The underground facility has around 40,000 square feet on two levels, underneath a (now dry) pond on the corporate grounds, designed to hold as many as 350 people for up to 3 months. Westland Oil didn’t last, going bust in 1987, and the camp was left empty for 13 years. In 2001 it was bought by Curtis Development, which hired the local Westlin Corporation to redevelop, market, and lease it. After hurricanes in 2005, companies began leasing the space, including Continental Airlines, which converted some of it for use as a crisis operations center. The building is now mostly being marketed as a secure data center, called The Bunker.

Ma Bell’s Bunkers
The corporation with the most underground space is—or was—AT&T. AT&T’s communications infrastructure of the 1950s to 1990s included hundreds of underground facilities, ranging from single story equipment vaults to multi-level underground system control centers.  Many of these were hardened concrete structures to help vital communication equipment survive a nuclear attack. It also reduced the likelihood of damage from vandals, as many of these facilities were unmanned, and sometimes very remote.

5071 The Rasor Road AT&T bunker. This AT&T facility is a typical large underground telco equipment vault. It is located along Interstate 15, between Los Angeles and Las Vegas, at the Rasor Road exit. The highway here follows a utility corridor, which includes major coaxial communication cables operated by AT&T. This is one of a few vaults on this stretch of desert highway between the two cities. Below the surface is 8,200 square feet of space, mostly in one large room, with a 20 foot ceiling. Inside would be equipment, generators, fuel, and maintenance machinery. On the surface is just a fenced two acre lot, with a small building containing the stairwell and crane hatch. The vault is under the lot, under two feet of concrete. This site was listed for sale a few years ago for $750,000. CLUI photoOne of the most common types of large underground telco vault can be found at repeater stations along the national microwave tower and coaxial cable networks. Staring in the 1990s, many of these facilities were sold off. If the site was on a hilltop near a commercial market, it might have been purchased by the American Tower Company, which leases space on towers to radio and cell companies, though the underground vaults remain mostly under-utilized. In some cases these vaults were purchased by private companies or individuals, and found new uses. Many remain on the market.

Larger underground AT&T facilities are generally found on mountain tops, accompanying antennas for long range communication. Some of these were designed to house members of the government, and  people designated by the government, during a national emergency, like a nuclear attack. One such site sits atop Short Hill Mountain near Harpers Ferry, Virginia. It was built by AT&T in the 1960s as part of the company’s communications infrastructure, and especially the part of it related to military communications. It is similar to four other facilities in the mid-Atlantic region known as Project Offices, which had large concrete parabolic tropospheric communication antennas, and an underground bunker of at least several thousand square feet, with a drive-in entrance. Four of the five Project Office sites are still in use in some form. At this site, in 2016, AT&T was proposing to build a 160,000 square foot building next to the underground building, but without being able to adequately specify its function, the plan was not supported by locals, and the company changed its mind. The large concrete antennas were removed a few years ago, in anticipation of this development.

Another AT&T Project Office site is known as the Chatham Big Hole Site, south of Chapel Hill, North Carolina, so-called because of the big hole that was observed by locals during its construction. The other Project Office sites are closer to the nation’s capitol, and the reason for this location, further away, is unclear. It is even more curious, as its communication connection to the others through the large tropospheric antennas was enabled through a relay facility, which was built at great expense. That site, the Buckingham Relay Site in Virginia, also had an underground facility, and is now out of service, and privately owned as part of a residence.

While some of these larger AT&T bunkers remain as part of AT&T’s mysterious infrastructure, some have been sold to individuals, or, more commonly, to other companies, once stripped of their now obsolete telecommunication functions. One such site is the AT&T Boone Tower bunker, in the farmland north of Des Moines, Iowa, which is now being marketed as an underground data center called the Infobunker. On the surface is a microwave relay tower, built as part of AT&T’s nationwide communications system in the 1960s. The bunker here, with around 20,000 square feet, was larger than a typical relay station, as it housed equipment for the AUTOVON system, which was a military communications network that existed independently of AT&T’s civilian network. Additional security included thicker walls, more space, bigger blast doors, and spring loading for equipment rooms.


There are a few dozen communications bunkers across the nation that were part of this system, some of which have been sold to the public. Even what was once one of the most important AT&T facilities in the nation is now in private hands. For more than a decade, the Netcong Bunker was the principal network operations center for AT&T. It is located on a hilltop in Netcong, New Jersey, not too far from the company’s later control center and headquarters in Bedminister and Basking Ridge. The Netcong center is in a 86,000 square foot, two level subterranean building, with walls of concrete more than 2 feet thick, and entirely cased in steel.  Communications lines once branched out from here all over the land, and through microwave links in the tower. The facility included accommodations and supplies for the 30 people who operated the center to live underground for up to three weeks.

Vital Records Incorporated purchased this facility from AT&T in 1995, and calls it the Roxbury Vault. The company has a smaller underground vault in Flagstown, purchased from AT&T in 1980. Though it operates a data center inside too, the company specializes in tape vaulting. Besides paper, microfilm, hard drives, and optical disks, another widespread form of records storage is magnetic computer tape, and some off-site underground storage locations are still referred to as tape vaults.

Governing Underground
The only entity to rival AT&T in the development of underground space is its partner throughout the Cold War, the US Government itself. Major underground military command and control centers exist underneath the Pentagon; at Raven Rock, Pennsylvania; and at Cheyenne Mountain, Colorado. At Offutt Air Force Base in Nebraska, the underground command center for Stratcom is being upgraded with a new $1.2 billion HQ right now.

And then there is FEMA, the bunker masters, operating out of the underground motherearthship, Mount Weather, in Virginia, with somewhere around 600,000 square feet of subterranean space, and accommodations for hundreds of government officials, if not thousands, including the president. (Many of these “federal arc” sites were covered in a 2002 issue of the Lay of the Land, so we won’t go into them any more here.

FEMA divides the nation into ten regional districts, each of which has an Emergency Operations Center (EOC), several of which are underground. Region 10, for example, covers Oregon, Washington, Idaho, and Alaska, and is based in Seattle, and is supported by a supply base with an underground EOC in Bothell, Washington. For Region 6, covering Texas, Oklahoma, New Mexico, Louisiana, and Arkansas, the supply base and EOC is in Denton, north of Dallas, where the Denton Federal Regional Bunker opened in 1964.

At that time, the Office of Civil Defense and Mobility, FEMA’s precursor agency, was planning on building major underground civil defense complexes in all eight of its regions (at Olney MD, Harvard MA, Thomasville GA, Battle Creek MI, Denver CO, Santa Rosa CA, and Everett WA). Denton was the first, and some of the others did get built, but not at this scale. It has two levels underground, with each around 25,000 square feet. Inside are communication facilities and, formerly, accommodations for up to five hundred people for 30 days. The office and reception center located above ground is still on site, and in use by FEMA.

5072 The Federal Emergency Management Agency’s regional operations center for New England is housed in this underground bunker in Maynard, outside Boston. Built in the early 1960s, when the agency was more concerned about nuclear attacks than it is now, the bunker has an operations room for organizing emergency relief teams throughout six New England states, and a variety of communications antennas on the roof of the building. CLUI photoFEMA does not have the only network of underground emergency operations centers. Many state, county, and even city agencies across the country have built their own emergency bunkers, some with accommodations for people to stay for long periods too (though not necessarily to wait out the fallout, but to rest between shifts while managing an ongoing crisis). Though not always underground, they are often located at communication sites, and may also house services such as call centers for local police. But some of them are deeply underground, like the Massachusetts Emergency Management Agency (MEMA) EOC, which is housed in a bunker on Route 9, near Framingham. With JFK directing the nation to build fallout shelters at the beginning of the 1960s, it perhaps is no surprise that his home state was among the most responsive in this regard. Originally, and allegedly, the operation center was intended to provide shelter for up to 300 state-selected people, including the governor.

The federal continuity of government program provided go-to bunkers for the departments and representatives of the primary federal agencies. An underground bunker in Harpers Ferry, Virginia, was reportedly for the Department of the Interior, and its Secretary. The bunker has a few thousand square feet of underground space. It is located on the campus of what is now the National Park Service’s national training center, and the bunker is now used by the Interpretive Design Center.

Between the end of the official Cold War, and the beginning of the official War on Terror was a moment of slack in defensive tensions, enough to even let some of the continuity of government bunkers and underground command centers find their way into the public.

The most famous of these is the Greenbrier Government Relocation Bunker, in West Virginia. Planned by the Eisenhower Administration and completed in 1961, this formerly secret underground bunker was designed to house members of Congress and their staffs during (and after) nuclear attack and is located below the Greenbrier Resort Hotel. Construction of a new hotel wing and expansion of its golf course served as cover for the bunker’s construction, starting in 1958. Inside is 112,544 square feet of space, to support a maximum of more than 1,000 people, with 18 dormitories, fuel storage, a cafeteria, power plant, water supply, hospital, meeting rooms, and an assembly room with a backdrop of the Capitol Building, for doing news reports. A pharmacy stocked current prescriptions for congressional members. In 1992, the bunker’s cover was blown by a Washington Post reporter tipped by sources who saw the bunker as outdated and unrealistic. In 1995, the government ended its lease with the hotel, and now the bunker is open for tours for $34 per person. Photography is not permitted on the tour, however. Probably more for marketing reasons than security concerns.  

Also in 1992, a former underground military control center in the mountains of western Massachusetts was sold to Amherst College, and is now a book repository. This 44,000 square-foot underground bunker, called the notch, was built in 1956 as a regional control center by the Strategic Air Command (SAC), which operated a bomber base nearby in Westover. The three story building features a self-contained water supply and electrical generation system, a cavernous “war room” with a glassed-in balcony, and accommodations for up to 300 people. In 1973, as SAC centralized its command centers in Nebraska and Colorado, the Federal Reserve Bank of Boston moved in and used it as an emergency back-up facility, and for records storage, along with New England Telephone and the New York Federal Reserve.

Private Survival Bunkers
An assessment of all the underground bunkers made over the course of the Cold War has yet to be made, and might be impossible. It would include thousands of backyard bomb shelters (and storm shelters too) built for family use, and numerous apocalyptic (or pragmatic, depending on your POV) group facilities, made by secretive survivalist preppers, and religious groups, like the Scientology bunker in Trementina, New Mexico (one of three operated by Scientology’s Church of Spiritual Technology), or the $25 million shelter complex at the Royal Teton Ranch, built for a few hundred members of the Church Universal and Triumphant, near Gardiner, Montana. President Kennedy, who led the charge for individuals to go underground, had several bunkers for himself, including one he could escape to while vacationing at the Cape, now rotting away next to a baseball field on Nantucket.

Though there are thousands of backyard bomb shelters and survivalist bunkers underground left from past and future fears of nuclear attack, one of the most unusual ones is in, or rather under,  Las Vegas. On the surface, it’s a more or less ordinary 1970s home on a one acre lot, at 3970 Spencer Street in a residential area. This is the caretaker’s house. Inside it is a staircase and elevator leading to a hollowed out cavern, whose walls are lit by a system that can create the impression of a day, night, or twilight sky. Inside the cavern’s 15,000 square feet of simulated outdoor space, with fake trees and lawn, is a main house, a guest house, swimming pool, putting green, and barbeque, all underground. It was constructed by a businessman and his wife, who claimed to be able to live there for a year without surfacing. It was sold in 2013 to a group called the Society for the Preservation of Near Extinct Species.

With so much of the motivation for going underground driven by the fears of nuclear attack, we would be especially remiss to not address the small matter of the two thousand or so underground missile silos across the country (450 of which are still locked and loaded, incidentally). Most of the 1,500 former silos and launch sites were imploded or otherwise destroyed when they were declared surplus, or obsolete. Their surface land was turned over to private citizens, usually banned from digging out the old silos, even if they could.
 
Not so in many other cases though, like the 72 Atlas F missile program sites from the 1960s, each with 180 foot-deep silos, as well as an underground launch control building. These are among the most favored silos for people who build them out into hardened underground homes, like the Survival Condo Project, which has two silos in Kansas, one of which is said to be sold out, with more than a dozen apartments going for more than $1.5 million.

More on this type of underground space later. The CLUI is working on a missile silo exhibition.   

What Goes Down Must Come Up
At the other end of the nuclear weapons underground spectrum from missile silos and Cold War bunkers is the other small matter of radioactive waste storage, which has resulted in two of the largest purpose-built underground facilities in the country.

The Waste Isolation Pilot Plant (WIPP) is the first major underground nuclear waste disposal facility to be built in the United States, and so far also the only one. This Department of Energy (DOE) facility east of Carlsbad, New Mexico, is a final disposal site for government-generated radioactive waste, including material from nuclear weapons production. The underground space was constructed in the early 1980s and finally received the first load of waste in the late 1990s. Designed to be a permanent, geological tomb for the material, the facility consists of a central mile-long corridor 2,150 feet underground, off of which are other corridors, and 56 one hundred yard long chambers for waste storage. There are 30 or so support structures at the surface, in a secure zone covering over 10,000 acres. All the waste disposed of at WIPP is from other DOE and military sites, and is of the low-level and TRU (trans-uranic) variety (none of it is commercial, spent-fuel, or high-level nuclear waste—that is slated for Yucca Mountain, Nevada, or not). The waste at WIPP is comprised of mostly irradiated laboratory material, such as gloves, protective clothing, and other disposable test equipment. The repository is built in a bedded salt formation, a geologic layer of salt that is expected to slowly encroach on the waste material, surrounding it and isolating it from the atmosphere and ground water. Work on the design of a “keep out” sign for WIPP that would remain legible for 10,000 years is ongoing.

The largest and likely the most expensive underground facility in the nation is one that is still incomplete, and may never see the light of day: Yucca Mountain Radioactive Waste Repository. Located on the western edge of the Nevada Test Site, Yucca Mountain is the only site being considered as an underground repository for the nation’s high-level commercial radioactive waste. So far $12 billion has been spent to study the site and partially build the repository, including a 25 foot wide exploratory tunnel extending for five miles. In 2008, the federal government suspended work on the project, and it is currently mothballed, awaiting the political will to restart it.

But who knows. These days anything seems possible. We may be entering a protracted underground renaissance. ♦