Xining is located on the eastern edge of Qinghai-Tibet Plateau and the upper reaches of Huangshui River. It is the political, economic, scientific and technological, cultural and traffic center of Qinghai Province with an average altitude of over 2,200 meters (about 7,217 feet). The activities of human beings in this region can be traced to 2,100 years ago.During the Western and Eastern Han Dynasties, owing to its developing agriculture, Xining was paid more attention due to its economic and martial significance. As well as being the important hinge between the central plains and the western part of China in ancient time, Xining was the most common passing channel of the famous Silk Road. Until now, it is still the only road by which to enter the hinterland of the Qinghai-Tibet Plateau.Ta'er monastery is located in a narrow valley close to the village of Lusar, and about seventeen miles southwest of Xining. It is a Buddhist monastery part of the historical Tibetan province of Amdo, now in Qinghai province of China. It was there in the former that Tsongkhapa, the founder of the Gelugpa (Yellow Hat) sect of Tibetan Buddhism was born in 1357 and was later founded in 1583. Its superior monastery is Drepung, immediately to the west of Lhasa. It was ranked in importance as second only to Lhasa.Qinghai Lake is a saline lake situated in the province of Qinghai, and is the largest lake in China. The names Qinghai and Kokonor both mean "Blue/Teal Sea" in Standard Mandarin and Mongolian. It is located about 100 kilometers (62 mi) west of the provincial capital of Xining at 3,205 m (10,515 feet) above sea level in a depression of the Tibetan Plateau in the traditional Tibetan province of Amdo. twenty-three rivers and streams empty into Qinghai Lake, most of them seasonal. Five permanent streams provide 80% of total influx.