Asia can be divided in five main physical regions: mountain systems,
plateaus, plains, steppes and deserts; also important are freshwater ecosystems and saltwater ecosystems.
The three main mountain systems are: Himalayas, Tien Shan and Urals. The Himalayas: The Himalaya mountains extend for about 2,500 kilometers,
separating the Indian subcontinent from the rest of Asia. The Indian subcontinent, once connected to Africa, collided with the Eurasian continent
about 50 million to 55 million years ago, forming the Himalayas. The Indian subcontinent is still crashing northward into Asia, and the Himalayas are
growing about 5 centimeters (2 inches) every year. The Himalayas cover more than 612,000 km2, a territory that covers the northern provinces of India and
almost all of Nepal and Bhutan. The Himalayas are so vast that they are composed of three different mountain belts. The northernmost belt, known as
the Great Himalayas, has the highest average elevation at 6,096 meters. Thebelt contains nine of the
highest peaks in the world, which all reach
more than 7,925 meters tall. This belt includes the
highestmountain summit in the
world, Mount Everest, which stands at 8,850
meters.
Tien Shan: The Tien
Shan mountain system stretches for about 2,400
kilometers, straddling the border between
Kyrgyzstan and China. The name Tien Shan
means “Celestial Mountains” in Chinese. Tien Shan also has more than 10,100square kilometers of glaciers. The largest glacier is Engil'chek Glacier, which is
about 60 kilometers longThe Ural Mountains: they extend for about 2,500 km on an indirect line from
north to south of Russia to Kazaajstan, and they are the oldest mountains in the world, with between 250 and 300 million years. Millions of years of erosion have