The USS Wasp, sunk at Guadalcanal, has been located definitively, and photographed by deep sea explorers. They had discovered the USS Hornet, and had a good idea where the Wasp likely was, but hadn't been able to locate it until recently. The USS Wasp was an Essex Class Aircraft Carrier in the US Navy, and was sunk by torpedo hits in 1942- it's exact placement on the seabed unknown until now.
Article is HERE.