The Mariana Trench is a 1,580 miles (2,540 km) long, 43 miles (69 km) wide break in the floor of the western, southeast of the Mariana Islands. The Mariana Trench is part a subduction zone between two tectonic plates. The western edge of the Pacific Plate is being pushed under the eastern edge of Mariana Plate. The valley is also notable as deepest place in the world's oceans. - AsNotedIn