The Datong Ancient City Wall is located in the center of the ancient city, with an area of 3.45 square kilometers and a square outline. The existing city wall was built by Xu Da of the Ming Dynasty on the basis of the old cities of Han, Wei, Tang, Liao, Jin, and Yuan, and was added in the fifth year of the Hongwu reign of the Ming Dynasty (1372 AD). It is a relatively complete ancient city wall building in China.