Horse caravan crossing 17th century stone bridge (1687) on the Cha Ma Gu Dao, at Heshun, a 600-year old town near Tengchong in southwest Yunnan, China. Close to the Burmese border, Heshun was an important trading town on what was originally the Southern Silk Road, then the Burmese section of the Tea Horse Road (Cha Ma Gu Dao), then in World War II the Burma Road.