Aerial view of Lake Manasarovar in Ngari, Tibet Autonomous Region on Sept. 9, 2018. (Photos: Xinhua)

The Ngari area has an average altitude of over 4,000 meters above sea level.

Aerial view of the ancient grottoes of Donggar on the hills in Ngari, southwest China's Tibet Autonomous Region Sept. 11, 2018.

The scenery of earth forest in Zanda County of Ngari, southwest China's Tibet Autonomous Region.

The earth forest is the sediment stratum of rivers and lakes in ancient times, formed by erosion of water. The Ngari area has an average altitude of more than 4,000 metres.