The blast doors are open.

The article offers information on the Diefenbunker, the massive four-level, 9,300-square-metre underground fortification was capable of withstanding a five-megaton blast from 1.8 kilometres away, commissioned by Prime Minister John Diefenbaker as part of his government's reaction to rising threats of nuclear conflict between the West and the Soviet Union. It mentions site allows visitors to travel back in time to the 1960s and the fear of nuclear attack.