|Hawaii Undersea Research Laboratory (HURL) researchers publicly release a partial video1 depicting an August 2013 discovery of the World War II Japanese Sen Toku-class I-400, an early submarine platform for surface launching aircraft.|
CSM, WWII submarine: Video of humongous 'lost' Japanese sub
University Hawaii, Giant World War II aircraft-carrying submarine discovered off Oahu coast
CombinedFleet, Discovery of Imperial Japanese Navy Submarine August 1st 2013
PBS, Secrets of the Dead, Japanese SuperSub (2010 programming)
1. Video link provided by a relatively mature Pisces-class deep submergence vehicle platform.
UPDATED 12/22/2013 Those interested in the behemoth I-400 class submarine may want to read the World War II book Operation Storm.
Halibut (SSN-587) sailors will appreciate the submarine's design—hangar storage of aircraft for surface launch.