The Pacific Ocean is the deepest ocean on Earth, reaching about 10,984 metres at the Challenger Deep.
The Challenger Deep lies within the Mariana Trench, east of the Mariana Islands in the western Pacific. Its measured depth varies slightly according to instruments and survey methods, but modern studies place the deepest seafloor close to 11 kilometres below sea level. The pressure there is more than 1,000 times atmospheric pressure at the surface.
The Pacific is also the largest ocean, covering more than 165 million square kilometres when marginal seas are included. It extends from the Arctic Ocean in the north to the Southern Ocean in the south and is bordered by Asia, Australia, and the Americas. The name comes from Portuguese explorer Ferdinand Magellan’s description of relatively calm waters in 1520.
The Pacific contains the Ring of Fire, a belt of volcanoes and earthquake zones around much of its edge. Subduction at ocean trenches drives much of this activity. The Mariana Trench is not the same thing as the entire Pacific; it is one particularly deep feature within the ocean.