Mountains of the World

A mountain is a large natural elevation of the Earth's surface that rises prominently above its surroundings, usually with steep slopes and a defined summit. Mountains form over long periods through geological processes, most commonly the collision and movement of the Earth's tectonic plates, which buckle and uplift the crust. Others arise from volcanic activity or from the erosion of high plateaus. The tallest mountains tend to occur along the boundaries where continental plates meet.

The greatest concentration of high peaks lies in the Himalaya and neighbouring ranges of Asia, formed where the Indian and Eurasian plates collide. Mount Everest, on the border of Nepal and Tibet, is the highest mountain above sea level. Other notable Himalayan and Central Asian peaks include Cho Oyu and Shishapangma in Tibet, while ranges further north contain summits such as Muztagata in Xinjiang and high peaks of the Qinghai region of China. Mountains exist on every continent, shaping climate, rivers and human settlement.

Conditions change markedly with altitude. As elevation increases, air becomes thinner and colder, so the same mountain can pass through several climate zones from base to summit. This creates a series of distinct habitats stacked by height, ending in bare rock, permanent snow and glaciers on the highest peaks. The reduced oxygen and harsh weather at great altitude make the highest mountains demanding and dangerous environments for both wildlife and climbers.

Frequently asked questions

How do mountains form?

Most large mountain ranges form when tectonic plates collide and push up the Earth's crust over millions of years. Volcanic activity and erosion can also create mountains.

What is the highest mountain on Earth?

Mount Everest, in the Himalaya on the border between Nepal and Tibet, is the highest mountain measured above sea level.

Why is it colder at the top of a mountain?

Air pressure and density decrease with altitude, so the thinner air holds and traps less heat, causing temperatures to fall as elevation rises.