NASA has published images of a long-forgotten nuclear base that was constructed up to 30 metres below a solid ice sheet at the height of fears about nuclear armageddon. One of the aeronautical organisation’s scientists discovered the huge subterranean ice bunker during a routine research mission.

While flying a cutting-edge autonomous plane over the Greenland ice sheet, Chad Greene from NASA’s jet propulsion laboratory spotted something unexpected under the miles of ice. Using the plane’s…