Tourists enjoy the beautiful scene on the shores of Lake Namtso, southwest China's Tibet Autonomous Region, June 2, 2011. Namtso Lake, more than 4,700 meters above sea and having a surface area of 1,920 square kilometers, is the salt-lake at the highest altitude in the world. (Xinhua/Wen Tao)

Photo taken on June 2, 2011 shows tourists take a stroll on the shores of Lake Namtso, southwest China's Tibet Autonomous Region. Namtso Lake, more than 4,700 meters above sea and having a surface area of 1,920 square kilometers, is the salt-lake at the highest altitude in the world. (Xinhua/Wen Tao)

Photo taken on June 2, 2011 shows tourists take a stroll on the shores of Lake Namtso, southwest China's Tibet Autonomous Region. Namtso Lake, more than 4,700 meters above sea and having a surface area of 1,920 square kilometers, is the salt-lake at the highest altitude in the world. (Xinhua/Wen Tao)