Tengchong in Baoshan, Yunnan, is located on the border with Myanmar. It was once a communications hub of the Silk Road. As a cultural and historical city, it is now a trading post for emerald. Tenchong is also well known for its hot sea and cluster of about 70 volcanoes. The hot sea is actually a group geothermal springs. They are not only a marvelous scenic area but also good for health and have been used as a sanitarium. [China.org.cn]