Along the northern side of the mountains ran the main Silk road trade route from China proper to the Tarim Basin and westward. The Altyn-Tagh and Qilians were sometimes called the Nan Shan ('south mountains') because they were south of the main route. Near the east end of the Altyn-Shan, the Gansu or Hexi Corridor ends and the Silk Road splits. One branch follows the Altyn-Tagh along the south side of the Tarim Basin while the other follows the north side.