Since 1997, the Diefenbunker Museum of Cold War history has occupied a 100,000-square-foot bunker just outside the Canadian capital of Ottawa. Commissioned in 1959 to become the heart of government in case of a nuclear attack, the bunker had a device designed to measure fall-out levels outside, to let evacuated government officials know when it was safe to emerge. Ahead of some planned renovations last year, the museum hired a specialist to check for any radiation coming from the device itself. It turned out to be perfectly safe. But while…
