Mount Everest is the world's tallest mountain as measured from sea level. But will it hold that title forever?
To answer this question, first we must understand how mountains form and how Mount Everest and the rest of the Himalayas got so tall. One way tall mountains form is when two tectonic plates collide. As one begins to subduct — or move under — the other, crust gets mushed around, upheaved, and turned into mountains.
