Mariana Trench

The Mariana Trench is a crescent-shaped oceanic trench in the western Pacific Ocean east of the Mariana Islands, roughly 2,550 kilometers long, and the deepest known point in any of Earth's oceans. Its deepest surveyed point, the Challenger Deep, reaches close to 10,900 to 10,935 meters below sea level depending on the survey, deep enough that the summit of Mount Everest would sit well underwater if placed there. The trench formed at a convergent plate boundary where the old, cold and therefore unusually dense Pacific Plate subducts beneath the smaller Mariana Plate, one of the steepest and fastest subduction zones on Earth, and its exceptional depth compared with other subduction trenches is generally attributed to the great age and density of the subducting Pacific seafloor there. Pressure at the Challenger Deep exceeds 1,000 times atmospheric pressure at sea level, and the site was first reached by descent in 1960 by the bathyscaphe Trieste, crewed by Jacques Piccard and Don Walsh. This entity documents the trench specifically as a named geological formation produced by oceanic subduction, a distinct facet from its treatment as a place and landform in the Geography Atlas.