The Challenger Deep is the deepest known point in the Earth’s seabed hydrosphere (the oceans), with a depth of 10,902 to 10,929 m (35,768 to 35,856 ft) by direct measurement from deep-diving submersibles, remotely operated vehicles and benthic landers and (sometimes) slightly more by sonar bathymetry.
The Challenger Deep is located in the Western Pacific Ocean, at the southern end of the Mariana Trench near the Mariana Islands group. According to the August 2011 version of the GEBCO Gazetteer of Undersea Feature Names, the Challenger Deep is 10,920 m (35,827 ft) ±10 m (33 ft) deep at 11°22.4′N 142°35.5′E. This location is in the ocean territory of the Federated States of Micronesia.
The depression is named after the British Royal Navy survey ship HMS Challenger, whose expedition of 1872–1876 made the first recordings of its depth. The high water pressure at this depth makes designing and operating exploratory craft difficult. The first descent by any vehicle was by the manned bathyscaphe Trieste in January 1960; unmanned visits followed in 1996, 1998 and 2009. In March 2012 a manned solo descent was made by film director James Cameron in the deep-submergence vehicle Deepsea Challenger. Between 28 April and 4 May 2019, the DSV Limiting Factor completed four manned dives to the bottom of Challenger Deep. Between 6 June and 26 June 2020, the DSV Limiting Factor added six completed dives. As of July 2020 the list of people who descended to Challenger Deep comprises thirteen people.