The Earth’s crust

The Earth's crust is the outermost layer of our planet, acting as a rigid shell that covers the Earth's surface. It varies in thickness—from about 5 kilometers (3 miles) under oceans to up to 70 kilometers (43 miles) under some mountain ranges. Composed mainly of solid rocks and minerals, the crust is where we find continents, ocean floors, and all terrestrial life. It is divided into large sections called tectonic plates, which slowly move over the semi-fluid layer beneath. This movement causes geological activity like earthquakes, volcanoes, and mountain formation. The crust is essential for supporting life and shaping the Earth's surface.