prefecture is at an average elevation of about 3,700 meters. The Yarlung Zangbo River, the mother river of Tibetan people, runs 424 kilometers from west to east through seven counties of the area. In addition, Shannan has 41 rivers all year round with the river area of 38,000 square kms. Tsetang town, the administrative office of Shannan prefecture and the fourth largest city in Tibet was formerly an important place. Tsetang is attracting more and more tourists because it serves as the jumping board for the exploration of Yarlung Valley. And there also is the famous monastery-Samye, which could be visited by ferry.