A mountain is a great lifting of the Earth's surface. A lot of mountains close together is called a mountain range. The existence of some mountains can give rise to volcanic eruptions. Some mountains are called volcanoes.

Most mountains come into being as a result of violent movements inside the Earth. During the 5000 million years of Earth's history, there have been many upheavals. The rock on the Earth's surface was thrown up and squeezed, often many times. Then it began to be eroded by wind and water. The layers of stone move horizontally. Above, other layers have just been laid down. The effect of the intervening force breaks bends and moulds.

Mountains now thou7sand of metres above sea level were once at the bottom of oceans. Proof? Marine animal fossils have been discovered at the summits! Mountains are not all the same age. The Alps are fairly young for they still have deep valleys and pointed summits. By contrast the Urals are from an older time: the pointed summits have been eroded and the valleys filled.