世界上最深的海是太平洋马里亚纳海沟。这个海沟位于西太平洋，从关岛东南方向延伸至马里亚纳群岛，是地球上最深的海洋地区，也是地球上最深的地方之一。这个海沟的深度达到了10994米，比珠穆朗玛峰还要深。这个海沟的深度是由于冲绳海槽在太平洋板块与菲律宾板块相碰撞时形成的。

The deepest sea in the world is the Mariana Trench in the Pacific Ocean. Located in the western Pacific, extending from Guam to the Mariana Islands, the Mariana Trench is the deepest oceanic area on Earth and one of the deepest places on Earth. The depth of this trench reaches 10994 meters, deeper than Mount Everest. The depth of the Mariana Trench is due to the collision between the Pacific Plate and the Philippine Plate, which formed the Okinawa Trough.