On December 6, 1941 a British submarine was lost somewhere off Cephalonia island (The Ionian Islands, Greece) coast. However, one sailor, named John Capes, managed to survive. He remained calm after the explosion that sank the submarine and although the ship went immediately down, he emerged to sea level from a depth of 52 meters. He was the only one who survived.
John swam to the coast of Cephalonia and was lucky enough to be found by the Greeks of the island, who helped him escape from the occupation army. The islanders had him hidden in their houses for 18 months. Later Capes managed to escape to Alexandria, Egypt, where the British army was stationed.
Nobody knew where exactly Perseus was when the Greek diver Kostas Thoktarides found the wreck. The remnants of an Italian sea mine a few meters away from the sunken ship solved the riddle: Perseus hit on a mine and the explosion sent the submarine and the crew to the bottom of the sea.