The Forbidden City was surrounded by a ten metre high city wall and enclosed by a moat of 52 metres wide. At each corner of the city wall, there is a magnificent watchtower. All of them were used for protecting the emperor and his imperial family.

• 紫禁城被一座10米高的城墙和一条52米宽的护城河所环绕，在各个城角都设有一个壮丽的角楼。所有这些建筑都是用来保护皇帝和皇家安全的。