The Challenger Deep is the deepest known point in the Earth's seabed hydrosphere, with a depth of 10,898 to 10,916 m by direct measurement from submersibles, and slightly more by sonar bathymetry. It is in the Pacific Ocean, at the southern end of the Mariana Trench near the Mariana Islands group. The Challenger Deep is a relatively small slot-shaped depression in the bottom of a considerably larger crescent-shaped oceanic trench.