Introduction to the Hailar Fortress ruins of the Japanese invaders: It is one of the seventeen military fortifications built by the Japanese Kwantung Army in Northeast China. It is the largest among them and the best preserved of its kind in China. . Hailar Fortress consists of 5 main positions and 4 auxiliary positions, with the Aobao Mountain and Beishan positions as the main positions, covering an area of 22 square kilometers.