Special Mention

The format of its wall varied in accordance with the topography and defense requirements. In plains or key passages it was built very high and solid，while relatively low and narrow on high and steep mountains to reduce the cost of money and man labor. In impossible places the wall-like mountain ridges were included in as a part，termed as“steep mountain wall”，or cut into cliffs as part of it, termed as“cut mountain wall".

In places like Juyong Pass，Badaling，and some in provinces of Hebei， Shanxi，and Gansu，the wall is usually 7一8m high，4一5m thick on top and 6- 7m at the bottom. Towards the inside on the top is a parapet wall about 1 m high in case of the soldiers' falling over，and that outwards is crenellated，about 2m high. The top of this side has breaches for watch，and holes below for shooting and sto- ning. In vital sections，the top is blocked by a series of crossing barrier walls in case the enemy climbed up.