Introduction to Xunshan Fortress: Xunshan Fortress is the best-preserved place in Dongning, covering an area of ​​236,000 square meters and divided into three floors: upper, middle and lower. At present, 1,163 meters of the main corridor have been cleared, and the rooms are 446 square meters. There are 21 large and small rooms such as command posts, military rooms, ammunition depots, pools, and pump rooms.