The Avatar and — yes, all irony aside — Titanic filmmaker is currently headed to the bottom of the Pacific’s Mariana Trench, which, at seven miles down, is the deepest part of any ocean, in a one-man submarine that he helped design. (Not the one at left, which was actually used on Cameron’s 1989 The Abyss.) “I grew up on a steady diet of science fiction at a time when people were living a science fiction reality,†he told the BBC, citing Jacques Cousteau, the famous sea explorer. On the dive, the first in 50 years and the second ever, Cameron plans to shoot footage for a documentary, collect rock and soil samples, and — obviously — to locate the Heart of the Ocean, which totally could’ve been carried by sea currents all the way from the north Atlantic.