The Himalaya Range or Himalaya Mountains, usually called the Himalayas or Himalaya for short, is a mountain range in Asia, separating the Indian subcontinent from the Tibetan Plateau. By extension, it is also the name of a massive mountain system that includes the Karakoram, the Hindu Kush, and other, lesser, ranges that extend out from the Pamir Knot.
Together, the Himalayan mountain system is the planet's highest, and home to the world's highest peaks, the Eight-thousanders, which include Mount Everest and K2. To comprehend the enormous scale of this mountain range, consider that Aconcagua, in the Andes, at 6,962 metres (22,841 ft) is the highest peak outside Asia, whereas the Himalayan system includes over 100 mountains exceeding 7,200 m (23,622 ft).
The main Himalaya range runs west to east, from the Indus river valley to the Brahmaputra river valley, forming an arc 2,400 km (1,491 mi) long, which varies in width from 400 km (249 mi) in the western Kashmir-Xinjiang region to 150 km (93 mi) in the eastern Tibet-Arunachal Pradesh region. The range consists of three coextensive sub-ranges, with the northernmost, and highest, known as the Great or Inner Himalayas.
Some of the world's major river systems arise in the Himalayas, and their combined drainage basin is home to some 3 billion people (almost half of Earth's population) in 18 countries. The Himalayas have profoundly shaped the cultures of South Asia; many Himalayan peaks are sacred in Hinduism, Buddhism and Sikhism.
Geologically, the origin of the Himalayas is the impact of the Indian tectonic plate traveling northward at 15 cm per year to impact the Eurasian continent, about 40-50 million years ago. The formation of the Himalayan arc resulted since the lighter rock of the seabeds of that time were easily uplifted into mountains. An often-cited fact used to illustrate this process is that the summit of Mount Everest is made of marine limestone.