What is the deepest point in the world's oceans?

The deepest point in the world’s oceans is Challenger Deep, a depression within the Mariana Trench in the western Pacific Ocean. Its seafloor lies roughly 10,900 metres below sea level, making it deeper than Mount Everest is tall above sea level.

Challenger Deep is not the name of the entire trench. The Mariana Trench is the much larger geological feature, while Challenger Deep is a small, slot-shaped set of basins at its southern end. Modern surveys identify western, central, and eastern basins, with measurements differing slightly because depth calculations depend on sonar, pressure sensors, sound-speed profiles, and the reference sea level used.

The feature was first detected during the 1872–1876 voyage of HMS Challenger, whose crew recorded an unusually deep sounding in 1875. The first people to reach the bottom were Jacques Piccard and Don Walsh aboard the bathyscaphe Trieste in January 1960. Film director and ocean explorer James Cameron made the first solo descent in 2012. The Tonga Trench and Java Trench are also extremely deep, but neither contains the ocean’s deepest known point.