The Mariana Trench, in the western Pacific Ocean east of the Mariana Islands, is the deepest oceanic trench on Earth. Its deepest known point, the Challenger Deep, reaches about 10,935 meters (roughly 35,876 feet) below sea level.
That is more than 2 kilometers (1.2 miles) deeper than Mount Everest is tall. The trench itself is crescent-shaped, about 2,550 km (1,580 miles) long and 69 km (43 miles) wide.
Source: Wikipedia, Mariana Trench