After World War II, when the former allies broke apart and the cold war started, the government of many countries started updating the defences. This was necessary with the new threat by atomic weapons. The result: numerous nuclear bunkers all over were built.
During the Cold War, every county council of Great Britain was required by the government to have a HQ for the case of a nuclear war. This buildigs were rather expensive and upkeep was expensive too. Sometimes the county councils bought abandoned bunkers from the war office.
1993, with the ending of the cold war, the government decided to remove the requirement for each county to maintain such an Headquarter. The county councils all over Britain made enormous cost saving by finally closing their command centres. Some of them were renovated, refurbished, and opened as a public tourist attraction.
However, small differences exist between todays museums and the time they were still in use. The heating for such a bunker is several hundred pound per hour or at least per day, depending on the size. This cannot be financed by the admission fees, and so the bunkers are often unheated today. This means temperatures around 8°C, similar to a cave.
Most atomic bunkers described on this pages are in Europe. But they were built all over the World, in East and West. Since the opening of eastern countries to international tourism, even some bunkers of the Warshaw Pact were opened to the public.