- Climbers and tourists visit them for the scenery.
- Farmers graze their animals on them.
- Water authorities make reservoirs and pump the water to towns and cities.
- Forestry companies grow coniferous forests and harvest wood on them.
It has been estimated that 12% of the world's 6.8 billion people live in mountain areas. That means there is about three-quarters of a billion (seven hundred fifty million) people living in mountain areas.
The Alps are the most densely populated mountain area in the world. Thirten million people live in the Alps.
Nearly half (46 per cent) of these people live in mountains in the Asia/Pacific region.
People as well as other animals and plants have adapted to living in the mountains. The South American Uru tribe have larger hearts and lungs to breather the thin air at high altitudes.
Mountains can make travel difficult.
Mountains can be very difficult to cross. They are often rugged and filled with forests and wild animals, such as bears and wolves. They may have no natural 'passes,' or easy places to cross the mountains. Mountains can also be hard to climb or may have ice or snow or glaciers that make travel dangerous.
All this means that crossing over mountains - to trade goods or to fight a war - can be tough to do. Sometimes, people who live surrounded by mountains feel very isolated from the world around them. It is just too difficult to cross over to other lands.
It has been estimated that a tenth of the world's population - about
half a billion people - lives in mountain areas.