Filmmaker James Cameron gives two thumbs-up as he emerges from the Deepsea Challenger submersible, March 26, 2012, after his successful solo dive in the Mariana Trench, the deepest part of the ocean. The dive was part of Deepsea Challenge, a joint scientific expedition by Cameron, the National Geographic Society and Rolex to conduct deep-ocean research.

James Cameron talks with his crew in front of the Deepsea Challenger following testing of the submersible in Jervis Bay, south of Sydney, Australia. The deepest point in the trench, known as Challenger Deep, is located southwest of Guam with a depth of nearly seven miles below the surface.

James Cameron sits inside the pressure sphere simulator at Acheron Project offices in Sydney, Australia. The actual sphere where Cameron sat aboard the Deepsea Challenger during his descent to the bottom of the Mariana Trench has an interior diameter of 43 inches, providing life support, communications and control of the submersible.

Crews examine the Deepsea Challenger submersible aboard the Mermaid Sapphire off the coast of Australia. If Mount Everest, the world's tallest peak, were fit inside the trench, there would still be nearly 1.3 miles of water above it.

The Deepsea Challenger submersible begins its first 2.5-mile (4-km) test dive off the coast of Papua New Guinea.

Jacques Piccard and U.S. Navy Lt. Don Walsh emerge from the bathyscaphe Trieste following their manned descent to the bottom of the Mariana Trench in January 1960. They spent only 20 minutes on the ocean floor and were unable to collect specimens or take photographs. Only unmanned vessels had descended to such depths since then until Cameron's successful dive.