A network of underground tunnels and bunkers used by the Nazis to develop an atomic bomb has been discovered in Austria by a filmmaker.
The complex was discovered just outside the small town of St Georgen an der Gusen, near Linz. Its exact location was determined using intelligence reports and radiation tests, which revealed higher than normal levels of radioactivity.
Andreas Sulzer, the filmmaker who is leading the exploration, discovered a critical 1944 report by the forerunner to the CIA, from an American spy who noted the existence of a secret weapons programme in the area.
The facility was built using slave labour from a nearby concentration camp, Mauthausen-Gusen.
Covering up to 75 acres, the vast site was believed to be connected to the underground Bergkristall factory, where the Messerschmitt Me 262, the first jet-powered fighter plane, was built.
Following the war, the factory was inspected by the Allies, but they never uncovered the well-hidden, secret complex.