Jiaohe was founded in the second century BC by the Han as an administrative center and garrison town. It lies between two rivers and on a cliff face, very much a natural fortress, though the city itself had no walls. It occupied a place of importance militarily, administratively, and economically along the Silk Road until the 13th century, when the invading Mongols under Genghis Khan laid waste to the area. Though it is not as extensive as the Gaochang Ruins, the ruins of Jiaohe are better preserved.