The Mariana Trench is in the middle of the Pacific Ocean. The Mariana Trench was formed through a process called subduction. Earth’s crust is made up of plates that float on the molten rock of the Earth’s mantle. While floating on the mantle, the plates slowly bump into each other and sometimes even collide. When two plates crash into each other, an oceanic plate (plates that are on top of the ocean) goes downward into the mantle, while the other plate goes up over the top. This causes a trench to be formed near the boundary of the two plates. That is how the Mariana Trench was formed!
