Killer Subs in Pearl Harbor

NOVA: A dive beneath the waters of Pearl Harbor could reveal new clues regarding the sinking of the USS Arizona in 1941. For decades, it has been thought that the Arizona was sunk by Japanese aircraft, but the discovery of a Japanese 'midget sub' near the scene of the battle raises questions about the Arizona's final hours. The submarine matches four other experimental vessels discovered in shallower water closer to the harbour entrance, and it is the only one that seems to have fired its torpedoes.