Why are there ocean basins, continents, and mountains?

Part of Hall of Planet Earth.

Exhibition hall with rock samples and explanation screens. The "Why are there ocean basins, continents, and mountains?" section of the Gottesman Hall of Planet Earth
AMNH / R. Mickens

Over millions of years, ocean basins open and close, continents move and change shape, and mountains are pushed up and eroded away. Such dynamic processes continually reshape the surface of the Earth. The movement of rigid plates on the Earth’s surface, known as plate tectonics, is the cause of these changes. Volcanic eruptions and earthquakes are dramatic hints of the great movements that take place over the vastness of geological time.