Those old enough to have lived through the Cold War will remember the constant and terrifying threat of nuclear attack.
With international tensions at a dangerously high level in the latter half of the 20th century, it is no surprise that the UK Government had plans in place to keep high-ranking members of the Government and Royal Family safe in case the worst came to pass.
Among these was the construction of a bunker buried 100 feet under Corstorphine Hill and beneath 10 foot of reinforced concrete, which was Scotland's first line of defence against the threat of a nuclear attack.
The Category-A listed structure was originally built during the Second World War to serve as the RAF's operations command centre for all of Scotland's radar stations. It was expanded and converted into a nuclear bunker in 1952.
In the event that the Queen and her family were at their residence in Edinburgh at the time of a nuclear attack, they would have fled to the bunker.
It was redesignated in the 1960s as part of a national scheme known as Regional Seats of Government (RSG) that was a secret until 1963, when their existence was unearthed by anti-war activist group Spies for Peace. RSGs were a network of civil defence bunkers from which the UK could be governed in the event of a nuclear attack.
One of the biggest subterranean military sites in the UK, the Barnton Quarry Nuclear Bunker was built over three storeys. The structure even contained a BBC broadcasting studio, and was large enough to house 400 people—including members of the military, the police, and the fire and ambulance services.
Since the Cold War never escalated into nuclear war, the bunker was no longer in operation by the 1980s. At this time, ownership was transferred to Lothian Region Council, who later sold it in the late 1980s to a private developer.
After this, the bunker was damaged by two separate fires in the early 1990s, rendering it unusable and full of asbestos. It was sold in 2005 to James Mitchell, owner of Scotland's Secret Bunker, who has worked with a team of volunteers to carry out restoration work.
The owner intends to open Barnton Quarry Nuclear Bunker up to the public as a museum after plans were approved by the City of Edinburgh Council.
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