Cold War Bunkers and Fallout Shelters: The Vaults Built for the Bomb

A Cold War bunker is a hardened shelter, usually underground or under heavy earth and rock, built between the 1950s and the 1980s to keep a government, a military command or ordinary people alive through a nuclear attack and its fallout. Think of it as a vault for people: thick doors, filtered air, its own water and power, and supplies for weeks.

Cold War bunkers at a glance

What is a bunker, and how is it different from a vault or a shelter?

A vault keeps things in and people out. A bunker has to keep people alive inside for days or weeks, which is a much harder brief: the door still matters, but so do the air, the water, the food, the toilets and the power. That’s why we call bunkers vaults for people. The engineering overlaps with the bank vault, but the bunker also has to breathe.

A fallout shelter is the smallest and simplest version. It isn’t built to survive the blast itself, only the radioactive dust that falls afterwards. The US shelter survey of the 1960s didn’t build new shelters at all: it looked for existing buildings that could take 50 people or more and gave enough protection, then marked and stocked them.¹ A bunker in the full sense, such as Cheyenne Mountain, is dug in deep enough to work through an attack, not just after one.

There’s a third word that turns up here: the secure room. Some of the work in these places was classified, and US rules still allow a temporary SCIF for compartmented intelligence to be set up in a building or a bunker. In practice the three blur. Most of the sites below had vault doors, sleeping quarters and a classified room or two.

Inside a Cold War bunker: doors, cover, air and supplies

We’re describing what the record says these places had, not how to build one. Every big bunker on this page shares the same short list of parts, and the published descriptions read almost like an inventory.

Blast doors: where the safe makers came in

The door is the part that connects bunkers to this site. Safe and vault makers had been designing against explosives for decades, though the explosives were the burglar’s: in 1909 Sumner Ely of the Ely-Norris Safe Company patented a round door with hidden chambers to take the gas of a blast.⁶ A nuclear blast door had a different job, holding back a pressure wave rather than a burglar’s charge, but the firms that knew heavy steel doors were the obvious ones to ask.

The best-documented case is the Mosler Safe Company. In the 1957 Plumbbob test series a Mosler vault was set where the blast would reach about 75 psi; the concrete on its sides was ripped off and the door trim loosened, but the steel door still worked.⁷ Around 1960 Mosler built the two blast doors for the vehicle entrances of the congressional shelter under the Greenbrier resort. The one photographed at the works is 19.5 inches thick and weighs more than 20 tons.⁸ Mosler had form with government vaults: its company history counted the Bullion Depository at Fort Knox among its jobs in 1936.⁹

Bunker doors outweigh most bank vault doors, and their weights are where sources disagree most. Cheyenne Mountain’s doors are 3.5 feet thick and 25 tons each according to Air Force Magazine, while an Air Force photo caption of 2012 calls them 20-ton doors.³¹⁰ The heaviest figure we found is 34 tons, for a door 10 by 20 feet at Mount Weather, and that comes from press reports collected by the Federation of American Scientists rather than from the government.¹¹ So take any single weight with a pinch of salt.

A timeline of Cold War bunkers, 1951 to 2004

Timeline

• 1951 Construction starts at Raven Rock, Pennsylvania; the Federal Civil Defense Administration launches “Duck and Cover”.
• c.1953 Kelvedon Hatch in Essex is built as an RAF sector operations centre.
• 1954 Tunnelling begins at Mount Weather, Virginia (finished 1958).
• 1958 Ground is broken for the congressional bunker at the Greenbrier, West Virginia.
• 1961 Excavation of Cheyenne Mountain starts in June; the fallout shelter sign is unveiled on 1 December.
• 1966 Cheyenne Mountain goes operational in April.
• 1968 Britain halves the number of Royal Observer Corps posts it maintains.
• 1974 The US fallout shelter programme is allowed to lapse.
• 1991 to 1992 The Royal Observer Corps stands down; the Washington Post exposes the Greenbrier bunker.
• 2004 The Burlington bunker at Corsham is declassified in December.

Sources for the timeline: FAS on Raven Rock and Mount Weather,¹²¹¹ the National Park Service on civil defence,¹³¹⁴ Subterranea Britannica on Kelvedon Hatch,¹⁵ NPR on the Greenbrier,⁴ Air Force Magazine on Cheyenne Mountain,³ ORAU on the sign,¹⁶ Historic England on the observer posts² and the Ministry of Defence on Corsham.⁵

America’s bunkers for government and the military

The US put most of its hideaways within a few hours’ drive of Washington, plus one fortress in the Rockies. These are the big four, kept short; each could fill a page of its own.

Raven Rock (Site R), Pennsylvania

Raven Rock sits just over the Pennsylvania state line near Waynesboro. The idea dates from 1948, President Truman approved the site in 1950, construction began in 1951 and the Alternate Joint Communications Center, known as Site R, was operational in 1953.¹² FAS describes it as still working today, as a disaster recovery site for military communications, and we found no public access. We tell the full story of Raven Rock, the underground Pentagon separately.

Mount Weather, Virginia

Mount Weather was the civilian government’s hideaway. Tunnelling began in 1954 under the code name Operation High Point and the underground bunker was finished in 1958. Press reports collected by FAS describe cots for 2,000 people, with private quarters only for the President, the Cabinet and the Supreme Court, and they record one full activation, during the Northeast blackout of 9 November 1965.¹¹ Before any of that, the land belonged to the Weather Bureau, which launched weather balloons and kites from it. It’s hard to imagine a gentler first career for a mountain.

Cheyenne Mountain, Colorado

Cheyenne Mountain is the one everyone has seen in films. Between June 1961 and April 1966 nearly 700,000 tons of granite were blasted out of the mountain near Colorado Springs, at a cost of $142 million for a 5.1-acre complex. Inside, 12 three-storey and three two-storey buildings stand on 1,319 steel springs.³ Office blocks on springs, inside a mountain. Small surprise the place turned up in films such as WarGames.³ The blast doors were often closed during the Cold War and were last shut for real on 11 September 2001. Despite the legend, the mountain never housed NORAD’s headquarters, and since 2008 it has been the alternate command centre for NORAD and US Northern Command.³

The Greenbrier, West Virginia

The strangest of the four was built under a luxury hotel. Government workers broke ground in 1958 on “Project Greek Island” at the Greenbrier resort in White Sulphur Springs, telling staff and guests the hole would be a conference centre, which it partly was. Behind three-foot concrete walls it had room for every member of the House and Senate and 1,100 beds, each assigned to somebody, and a crew posing as TV technicians from “Forsyth Associates” kept it ready for 30 years until the Washington Post exposed it in 1992.⁴ Its Mosler doors are described above, and we tell the full story of the congressional bunker under the Greenbrier separately.

Money had a bunker too. The Federal Reserve dug its Communications and Records Center into Mount Pony at Culpeper, Virginia, dedicated in 1969 and said to have held a stock of cash to restart the economy after an attack.¹⁷ It’s in our list of the world’s strangest vaults, and today the Library of Congress keeps films there.¹⁸

Public fallout shelters and the yellow-and-black sign

For most Americans the Cold War bunker wasn’t a mountain. It was a school basement with a metal sign by the door. Early civil defence in the 1950s had swung from shelters to mass evacuation and back again, as warning times shrank and traffic plans looked hopeless.¹³ Then came the Berlin crisis.

Kennedy’s answer, by late 1961, was the National Fallout Shelter Survey and Marking Program. Architects and engineers surveyed public and private buildings, and those that qualified were marked with signs showing where the shelter was and how many it held. That October he asked for $207 million to identify, label and stock shelters in existing buildings.¹⁴ Congress had already voted more than $169 million for shelter work in 1961.¹

The sign was introduced on 1 December 1961 and was meant only for federally approved shelters. The Office of Civil Defense first thought of using the radiation warning symbol, then dropped it, because a shelter means safety and the trefoil means danger. Its fact sheet chose yellow and black as the colours psychologists found most eye-catching, and the result was three yellow triangles, points down, in a black circle, readable at up to 200 feet. Contracts in 1962 covered 400,000 aluminium outdoor signs and a million steel indoor ones, with overlay numbers to show the capacity in the circle.¹⁶ The designer, the supplies and the buildings that still carry one are in our article on the fallout shelter sign.

Look at a surviving sign and you’ll often see that capacity number still in the circle, like the 260 in the photo. To a designer’s eye, it has aged better than anything else the programme produced. Credit usually goes to Robert Blakeley, a mid-level official in the Army Corps of Engineers, though the Office of Civil Defense fact sheet speaks of design contracts with graphic arts studios advised by a psychologist.¹⁹¹⁶ We couldn’t reconcile the two accounts.

The shelters themselves were less tidy than the signs. Stocking with water, “survival biscuits”, medical and sanitation kits and radiation meters began in October 1962, just before the Cuban Missile Crisis showed how few designated shelters were ready, and in the end only about a third of them were stocked with two weeks’ supplies.¹⁴ Private shelters never caught on either: an estimated 200,000 by 1965, about one for every 266 households. Surveying and stocking went on until 1970 and the programme lapsed in 1974.¹⁴ If there’s an old sign on a building near you, it marks history, not a stocked shelter.

Britain’s secret bunkers

Britain’s network was layered like a chain of command, from a hole in a field to a town under Wiltshire. The smallest pieces are the most numerous, so we start there.

Royal Observer Corps posts

From 1957 the Royal Observer Corps reported nuclear explosions and tracked fallout for the UK Warning and Monitoring Organisation. It worked from 1,518 underground posts, 1,026 of them in England, built from the late 1950s and largely finished by 1965, in clusters of three or four reporting to a group headquarters.²

Each post followed a standard 1956 Air Ministry design: a reinforced concrete box under an earth mound, reached by a ladder shaft about 4.6 metres deep, with a monitoring room about 4.6 by 2.3 metres for a crew of three, meant to be self-sufficient for 21 days. On the surface there’s not much to see: a hatch, a vent, and the mounts for instruments such as the Bomb Power Indicator and a pinhole-camera Ground Zero Indicator.² Half the posts went in 1968, and the rest closed when the corps stood down in 1991.²

The posts reported to group controls such as the York Cold War Bunker, built in 1961 as No. 20 Group headquarters. Most of the corps stood down on 30 September 1991 and the bunker network closed in March 1992; English Heritage took over the York bunker in 2000.²⁰

Kelvedon Hatch, Essex

Kelvedon Hatch is the bunker most British searchers are looking for. It was built in about 1953 as the sector operations centre for the Metropolitan Sector of RAF Fighter Command, part of the ROTOR radar project. Later it became the Home Office’s regional bunker for London: a sub-regional control from 1967, a sub-regional headquarters from 1973 and a Regional Government Headquarters from 1985. In the wartime chain it sat below the central government site at Corsham.¹⁵

In 1993 it was sold to Michael Parrish, who owns the farm around it, and he opened it as a Cold War museum.¹⁵ We follow it from radar station to museum in our full history of the Kelvedon Hatch nuclear bunker. From the outside you’d walk past it: the way in is through a modest bungalow in the woods, with the radio mast giving the game away.

Burlington, the government’s bunker at Corsham

Under Corsham in Wiltshire lie old Bath stone quarries that the army turned into an ammunition depot in the 1930s. In the 1950s part of Tunnel Quarry, known as Site 3 and code-named Burlington, was prepared to take some 4,000 central government staff, the Prime Minister among them, in a nuclear war. It had medical facilities, kitchens, canteens, offices, dormitories and its own communications.⁵ The Ministry of Defence took it over in 1991, emptied its fuel and food, drained its reservoir and declassified it in December 2004. It’s still on the MoD estate.⁵ We like the Ministry’s own phrase for it: an “underground city”.

Other countries: Switzerland’s shelter for everyone

Switzerland went further than Britain or the US: it set out to shelter its whole population, and it’s still at it. Switzerland’s first regulations on shelters were passed on 4 October 1963, and the law says every inhabitant must have a protected place that can be reached quickly from home.²¹ Today the Federal Office for Civil Protection counts around 370,000 private and public shelters. If a new building has no shelter, the owner pays a fee of CHF 1,400 per shelter place instead, and that money helps keep existing shelters in repair.²²

It isn’t only about nuclear war. The office says the shelters are mainly designed for armed conflict, but can also serve as emergency accommodation in disasters.²² Back in 2006, by swissinfo’s figures, coverage stood at 114 per cent: more shelter places than people.²¹

What happened to the bunkers after the Cold War

The end of the Cold War left both countries with hundreds of very solid buildings and no obvious use for them. Some kept working: Cheyenne Mountain is busier now than in the Cold War, according to the officials Air Force Magazine spoke to in 2016.³ Others found second careers. Part of the Greenbrier bunker is a tourist attraction and another part is used for secure data storage.⁴ Mount Pony went to the Library of Congress, which built 124 vaults there for nitrate film.¹⁸

In Britain, Kelvedon Hatch went back to the farming family and became a museum; York’s group control is an English Heritage site; and some observer posts are now listed buildings, like the one at Brandsby in North Yorkshire, which reported to York until 1991 and has since been restored.¹⁵²⁰² Burlington, emptied and declassified, stays in the Ministry of Defence’s hands.⁵ It’s a little odd to think of a protected monument the size of a garden shed, but that’s what a good many of these posts have become.

Can you visit a Cold War bunker?

A few, yes. Check opening times with each site before you go; ours is a history page, not a booking guide.

Cold War bunker myths

Sources for the myths: Air Force Magazine on Cheyenne Mountain;³ the National Park Service on shelter stocking and private shelters;¹⁴ NPR on the Greenbrier;⁴ and the Swiss Federal Office for Civil Protection.²²

Frequently asked questions