Tian Shan or Tien Shan (both: tēĕn shän) [Chin.,=celestial mountains], mountain system of central Asia, extending c.1,500 mi (2,410 km) from the Pamir Mts., Tajikistan, NE through the Xinjiang Uygur Autonomous Region, NW China, to the China-Mongolia border; Pobeda Peak (24,406 ft/7,439 m), on the Kyrgyzstan-China line, is the highest point. The E Tian Shan are relatively low parallel ranges that divide the Dzungaria and Tarim basins; the W Tian Shan separate into numerous complex branches. Some of the Alatau ranges are extensions of the Tian Shan. Because of the dry climate, the Tian Shan's snow line is generally above 11,000 ft (3,350 m). The Syr Darya, Chu, and Ili are the largest of many rivers that rise in the system. Issyk-Kol, W Tian Shan, is one of the world's largest mountain lakes. Coal, iron, lead, and zinc are mined in the region; grains are the predominant crop in the valleys. China and Kyrgyzstan and Kazakhstan are linked by several passes, notably the Terek Pass (alt. 12,730 ft/3,880 m) on the route connecting Kashi (Kashgar) and Samarkand.