Diefenbunker Eastern Ontario

During the Cold War, paranoid officials commissioned this gargantuan four-floored, secret subterranean bunker, designed to allow the government to operate safely underground for 30 days during a nuclear attack. Descend over 20m to highlights including the prime minister’s suite, the CBC radio studio and the Bank of Canada vault. Admission includes an optional one-hour audioguide; alternatively, guided tours leave at 11am and 2pm, with extra tours at 10:30am and 1:30pm in July and August. It’s about 40km west of town, just off Hwy 417 in the village of Carp.