The Ancient City Walls were built in the period 1374 to 1378. They were placed on the foundaion of the wall around the TangDynasty (618-907) .Since the location of Xi'an gives it strategic military importance, the Walls are very tall and were fortified. The eastern wall measures 2.590 metres, the western wall is 2,631.2 metres, the southern wall measures 3,441.6 metres, and the northern wall is 3,244 metres. totalling 11,906.8 metres. Much of the magnificent 600-odd-year-old wall is still standing and it is one of the best examples in China of an outstanding traditional city defense system and urban design. 

Album of Ancient City Wall,Check here!