Buried underneath the Greenland ice sheet is the legacy of a spectacular American failure. Camp Century was a hidden US military base, a network of tunnels that was supposed to expand from its originally limited scope during the 1950s into a sprawling complex of missile silos and troop accommodation.

Washington’s top secret Project Iceworm was intended to establish mobile launch sites for nuclear weapons beneath the ice that could survive a first-strike attack on the United States. The US government never sought consent for the scheme from Denmark, which was responsible for Greenland’s security.

Predictably, perhaps, this grand project didn’t work, and the site had been abandoned for good by 1967. The US military left their tunnels as they were, deeming the equipment within them too expensive to transport out. Due to the ice sheet warping and shifting over the intervening decades, the base is now located at least 30 meters below the surface. The waste left behind will be a problem for some future generation to deal with.