46 kilometers (29 miles) southeast of Turpan near the "Flaming Mountains" seat an impressive ruins of the ancient city of Gaochang. Built in the first century B.C. called Gaochangbi, it used to be a garrison town and later became a key point along the ancient Silk Road. By the seventh century it held sway over 21 other towns. The practice of Buddhism led to the establishment of many monasteries and temples here. In the ninth century, the Uigur established the Kharakhoja Kingdom here and Manicheamism flourished. The city was burnt down around the 14th century, during a period of warfare lasting 40 years.
The ruins originally consisted of three parts: the inner and outer cities, and a palace complex. The outer city extended 5.4 kilometers (3.4 miles) long with 11.5-meter-(38-foot-) high and 12-meter-(40-foot-) thick enclosure walls. Some section of the tamped earth reinforced with adobe. Nine city gates were built on cardinal points, three in the south and two in each other three directions respectively. Visitors are usually suggested to enter the best preserved one in the west to the core.
The inner city is a 3-kilometer (1.86 miles) long rectangle of which the western and eastern sections are well preserved. In the northern part of the inner walls is the Palace City. It shared its southern wall with the inner city. A square adobe pagoda called "Khan's castle"
which means "Imperial Palace" stands on a high terrace in the very north. Somewhat to its west a half-underground, two-storied structure was supposed to be the palace ruins. Several earthen platforms are still visible.
Two temple remains, one in the southwestern and other in the northwestern parts of the outer city are sightworthy. The first one, 130 meters (427 feet) long from east to west, 85 meters (279 feet) wide from south to north covers 10,000 square meters. It consists of an arched gate, courtyard, a lecture hall, a library of sutras, a main hall and the monks' dormitory. It is said that Xuanzang the renowned Buddhist monk of the Tang period had lectures here in the year of 628 on his way to India. The second is smaller but the murals remains are impressive.
The 5.4 kilometer wall of the square outer city is 11.5 meters high and 12 meters thick. The wall is built of tamped earth, with some sections repaired with adobe. There are two gates on each side of the outer city and the two on the west side with defense enclosures outside the gates are the best preserved.
The rectangular palace city is in the northern part of the city of Gaochang and it shares the north wall with the outer city and uses the north wall of the inner city as its south wall. There are still several three to four meter high earthen platforms in the palace city where the court of Huigu Gaochang Kingdom was seated.
In the north-central part of the inner city, there is a high terrace on which stands a square pagoda built of adobe called "Khan's castle" which means "Imperial Palace". Somewhat to its west there is a half-underground two storey structure which was probably the ruins of a palace.
In the southwestern part of the outer city there is a temple which is 130 meters long from east to west, 85 meters wide from south to north and covers an area of 10,000 square meters. The temple consists of an arched gate, a courtyard, a lecture hall, a library of sutras, a main hall and the monk's dormitory . Murals remaining in the main hall are still visible.
The renowed Buddhist monk Xuan Zang of the Tang Dynasty is said to have lectured in the temple for more than one month in the year 628 on his way to India to obtain Buddhist scriptures. In the vicinity of the temple there are also ruins of workshops and market sites. In the southeastern part of the outer city there is a smaller temple, the ruins of the murals within which are better than those in the main hall.
The construction of the city of Gaochangbi was a key point on the ancient Silk Road, but after many changes in fortune over a period of 1,300 years, and under the jurisdictions of the Gaochang Prefecture, the Gaochang Kingdom, the Xizhou Prefecture, HuiguGaochang Kingdom and Huozhuo Prefecture, the city was burnt down in the fourteenth century.

The city was brought under the protection of the state in 1961.