This document provides information about major geographic features of the Earth. It defines and describes deserts, peninsulas, islands, continents, mountains, rivers, streams, and oceans. Deserts cover approximately one-third of the Earth's land and form in low-lying areas where precipitation is blocked. Peninsulas are lands surrounded by water on three sides, connected to the mainland by an isthmus. Islands are smaller than continents and surrounded by water. The seven continents are named. Mountains are formed by geological forces and uplift in the Earth's crust over long periods. Rivers, streams, and creeks refer to flowing water but differ in size. Oceans cover most of the Earth's surface and there are four