We often hear about Nazi super-weapons — there was a whole cable channel dedicated to Hitler, wasn’t there? — but the Japanese had submarine aircraft carriers by the end of the war:
The I-400 subs were the largest ever built until the Ethan Allen-class of nuclear subs in 1961. The I-400 subs not only could travel one and a half times around the world without refueling, they carried three Aichi M6A1 attack planes, which they launched off their bow when surfaced, effectively making them underwater aircraft carriers.
Soon after the war, the US Navy sank the captured super-subs, to test its new top-secret “robot” torpedo — but really to keep them out of our supposed Allies’ hands:
The Hawaii Undersea Research Laboratory, or HURL, has found the rusting hulks off the coast of Oahu.
Now all they need is a little clean-up and a Wave Motion Engine…