University of Hawaii researchers have discovered the wreck of a giant (400 feet long!) Japanese submarine aircraft carrier in 2,500 feet of water off Oahu. Captured at war's end, the I-400 and I-401 carried three float-plane bombers intended to strike targets such as the Panama Canal, San Francisco, and even New York (the subs had a range of 37,500 miles!). Unwilling to share such advanced technology with the Russians in accord with WW2 treaties, the US scuttled the subs off Oahu.

Man, am I bummed that they're so deep. What an incredible dive those wrecks would be!