The ruins of the Jiaohe ancient city can be seen in the Yaernaizi Valley in western suburbs of Turban City in Xinjiang Uygur Autonomous Region. The valley was created by floods in remote antiquity and in its centre, there is a willow leaf-shaped platform which is 1650 metres long and 30 metres wide. Surrounded by steep rocks, the valley is about 30 metres deep. According to historical data, here used to be the location of the capital of the Frontal Kingdom of Cheshi. During the Sixteen Kingdoms Period and the Northern Dynasties (304-581 AD), this was the seat of Jiaohe Prefecture of Gaochang Kingdom, which became the seat of Jiaohe County of Gaochang Prefecture after the 14th year of Zhenguan Reign in the Tang Dynasty (640 AD).