Oceanic trench

Oceanic trenches are long, narrow, prominent depressions in the ocean floor, typically 50 to 100 kilometers wide and 3 to 4 kilometers deeper than the surrounding seafloor, though some run for thousands of kilometers in length. Roughly 50,000 kilometers of oceanic trench exist worldwide, most of them around the Pacific Ocean, with others in the eastern Indian Ocean and a few additional locations; the deepest point ever measured in the ocean lies within the Challenger Deep of the Mariana Trench, at 10,994 meters below sea level.