The submarine was reported lost Aug. 16, 1942.  Underwater video footage captured by an expedition hired by sons of the commanding officer, Lt. Cmdr. Mannert L. Abele, allowed the Navy to confirm the discovery.

Japanese anti-submarine attack data recorded no attack in the Aleutian area at the time of the Grunion's disappearance, so the submarine's fate remained an unsolved mystery for more than 60 years, the US Navy said.

The British submarine HMS Olympus, sank in 1942 at the height of the siege of Malta and is one of the most historic wrecks off the coast of this island.

The discovery of the wreck completes a historic and tragic story. During the height of the German and Italian blockade of Malta, the British Navy fought a constant battle to keep the valiant Island supplied with food, fuel and war supplies. Submarines were an essential part of this operation, both in bringing in supplies and defending the merchant shipping.