Sanying was built in Chenghua period of Ming Dynasty. It was originally built to defend against Japanese pirates, and was later used to defend against other foreign enemies. During the Qing Dynasty in China, Sanbao gradually became one of the important defense facilities in Beijing.
The design of three batteries embodies the excellent technology of traditional architecture and national defense engineering in China. According to historical records, the main building of the fort is a masonry structure, with a height of more than ten meters and a three-story observation deck overlooking the surrounding terrain of Beijing and finding the invading enemy. At the same time, there are underground warehouses, underground passages and other defense facilities under the third battery in case of emergency.
Nowadays, the Three Batteries has become an important cultural tourist attraction, attracting many tourists to watch it. By visiting the Three Batteries, people can understand the subtleties of China's traditional culture and national defense projects.