Introduction to Gaochang Ancient City: Gaochang Ancient City is located in the Mutugou River Delta at the southern foot of the Flame Mountain, 27 kilometers east of Turpan City. It was built in the Han Dynasty in the 1st century BC and is one of the treasures of the world's religious and cultural gatherings. Gaochang Ancient City is rectangular in shape with a circumference of 5.4 kilometers and is divided into three parts: the outer city, the inner city, and the palace city. The base of the outer wall is 12 meters wide and the wall height is 11.5 meters. It was built by rammers. There are nine gates in the city, and the west and north gates are the best preserved. Gaochang City was abandoned during the wars at the end of the 13th century, and most of the buildings disappeared. Currently, two temple ruins are preserved in the southwest and southeast corners of the outer city that are well preserved. There is a small irregular square castle in the middle of the northern part of the inner city, which the locals call "Khan's Fort".