A mountain is a landform that extends above the surrounding terrain in a limited area.
A mountain is generally higher and steeper than a hill, but there is considerable overlap, and usage often depends on local custom.
Mountains cover 54% of Asia, 36% of North America, 25% of Europe, 22% of South America, 17% of Australia, and 3% of Africa.
As a whole, 24% of the Earth's land mass is mountainous.
Also, 1 in 10 people live in mountainous regions.
Mountains are generally given as heights above mean sea level.
The Himalayas average 5 km above sea level, whilst the Andes average 4 km.
Most other mountain ranges average 2-2.5 km.
The highest mountain on Earth is Everest, 8,848 m, set in the world's most significant mountain range, the Himalaya.
The altitude of mountains means that the tops exist in higher cold layers of the atmosphere.