Just outside Ottawa sits a modest building that hides one of Canada’s most fascinating secrets: a four-storey underground Cold War–era bunker, built to house government officials in the event of a nuclear attack.

The site was nicknamed the Diefenbunker after Prime Minister John Diefenbaker, who commissioned it in the 1950s. Now a museum, visitors can explore decontamination chambers, the Prime Minister’s office and a vault meant to protect the Bank of Canada’s gold reserves.

Inside the Diefenbunker: the secret Cold War bunker built to protect Canada’s elite

Canada’s most famous attractions and their secrets