Summary
Highlights
The Earth's surface is covered by land and water, forming various natural features called landforms. The two largest types of landforms are continents and oceans. Continents are the largest landmasses, traditionally divided into seven: Asia, Africa, North America, South America, Antarctica, Europe, and Australia. Oceans are large areas of saltwater connecting these continents, divided into five main oceans: the Arctic, Atlantic, Indian, Pacific, and Southern Oceans. Oceans cover about 70% of the Earth, with the Pacific being the largest and deepest.
Smaller landforms are created through processes like erosion by wind and water, volcanic activity, and shifting tectonic plates. Mountains, recognizable for their steep sides and high peaks, are often formed when rock layers are pushed together, forcing land upward. Smaller, less steep versions are called hills, and low areas between mountains are valleys. Volcanic activity can also form mountains or even new land and islands when lava flows into the sea.
An island is a piece of land completely surrounded by water, varying in size. Greenland is the largest island, while Australia is considered a continent due to its immense size. Peninsulas are pieces of land with water on three sides, connected to the mainland on the fourth, like Italy and Florida. Isthmuses are narrow strips of land with water on both sides, connecting two larger landmasses, such as the Isthmus of Panama.
Coastal areas feature unique landforms like bays, coral reefs, lagoons, and estuaries. An estuary is where a river meets the sea, mixing freshwater with saltwater and creating shallow areas. Rivers themselves are important natural features, fed by rain or melted snow. They contain freshwater, starting in high ground and flowing downwards, with smaller streams joining to form larger rivers that eventually reach the ocean.
Before reaching the ocean, rivers may flow into lakes (large bodies of water surrounded by land) or ponds (smaller bodies of water). Most lakes are freshwater, though some, like the Great Salt Lake, are salty. Plains are large, flat areas of land without hills or mountains, such as the Great Plains. Plateaus are large, raised areas of land that are flat on top, often formed by volcanic activity pushing the land upwards without breaking the crust.