Jinshanling section of the great wall forms an impregnable and distinctive defense system by conterminous passes and watchtowers , layer upon layer of walls , and interlacing zones of fire , where such military facilities as warehouse towers , jinshan towers and single - side walls are typical along the great wall 金山岭长城城关相连、敌楼相望、重城护卫、射界交叉，组成了一道严密独到的防御体系，其中有许多军事设施如库房楼、大、小金山楼、单边墙等为万里长城所罕见。
