The Challenger Deep, located in the Mariana Trench in the western Pacific near Guam, lies at a depth of 35,840 feet and could easily hold the 29,029-foot Mount Everest.
The Deep was discovered in 1875, and people have been attempting to precisely measure its depth ever since. The first manned mission was made in 1960 by Swiss oceanographer Jacques Piccard and U.S. Navy Lieutenant Don Walsh in the customized bathyscaph Trieste. After a descent lasting nearly five hours, they reached the bottom of the Deep, staying for 20 minutes.
The next two vessels to reach the bottom of the world were unmanned, remotely operated underwater vehicles (ROVs): the Japanese submersible Kaiko, in 1995, and the U.S. vessel Nereus, which in 2009 collected samples of water and rocks from the bottom and brought them back to the surface.
Oscar winner hits the bottom
James Cameron is best known for another deep-sea expedition, the filming of the 1997 blockbuster film Titanic, but his trip to the bottom of the Deep aboard the submersible Deepsea Challenger is an even greater achievement. He spent three hours exploring the featureless seafloor, which he filmed with 3-D cameras.