The Earth’s crust is made up of a number of different plates that fit together like a puzzle. These plates can be made up of either continental crust or oceanic crust. The plates move around slowly, driven by the movements of Earth’s mantle. There are three main types of plate boundaries: divergent boundaries, convergent boundaries, and transform boundaries. Divergent boundaries are where two plates are moving away from each other, forming mid-ocean ridges and rift valleys. Convergent boundaries occur when two plates are moving towards each other, often causing subduction zones and mountain ranges. Transform boundaries are where two plates are sliding past each other, causing earthquakes.