Deep

This is James Cameron's new toy, a one-man (him) submarine with a working depth that will allow it to go anywhere in the ocean - even down to the very deepest spot on Earth, the slot canyon known as Challenger Deep in the Mariana Trench (some 36,070 ft, much deeper than an inverted Everest). Challenger Deep has only been visited by humans once before, in 1960, and then only briefly. James will be able to stay down there for hours.

Incidentally, Challenger Deep is named after the first ship to sound that area in 1875, the HMS Challenger, which is also the namesake of our Space Shuttle Challenger.