The Deepsea Challenger submersible with James Cameron inside is moved into place to begin its descent 7 miles below the surface of the Pacific Ocean to the Mariana Trench. The movie director spent more than three hours inside the trench. (National Geographic via Associated Press)

The Deepsea Challenger submersible with James Cameron inside is moved into place to begin its descent 7 miles below the surface of the Pacific Ocean to the Mariana Trench. The movie director spent more than three hours inside the trench. (National Geographic via Associated Press)