Introduction to the city wall: The total length is 5744 meters and the area is 130 hectares. The terrain is flat to the east and adjacent to Bada Mountain to the west. It is in the form of a flat mountain city. There are four gate towers, two water gates, There are three hollow piers, two general towers, two crossbow towers, five pavilions, five gun towers, four turrets, five secret doors, one beacon pier, four enemy towers, nine outer walls, two sewers, etc. 48 facilities make up the city wall, but due to floods and wars, 7 facilities (a water gate, a hollow pier, a secret door, two enemy towers, and two sewers) were damaged, and now only four facilities remain.