In 2005, dive researchers from the University of Hawaii discovered the remains of a massive Japanese submarine, I-401. This behemoth was basically an underwater aircraft carrier and was built to bomb the Panama Canal–it carried three folded up bombers inside its watertight hangar.

The huge submarine could sail 37,000 miles, or one and a half times around the world. Three of these subs were captured at the end of the war. They measured 400 feet long and 39 feet high, and could carry a crew of 144 men.