Short note on the tea horse road

The Tea Horse Road ,or Cha Ma Gu Dao in Chinese ,linked southwest china to Tibet then to northern India .the length is 5000km .the term is originated in the Tang dynasty (618 to 907).it was a web of foot and mule caravan pathsand  trade routes  that linked  western of Sichuan ,western of Yunnan ,Qinghai and Tibet across some of the most grueling and dangerous terrain in Asia.