National 1A Tourist Attraction. Located in Zhangfang Town, Fangshan District, Beijing, about 75 kilometers from the urban area of Beijing. It belongs to a thematic cultural tourism attraction. It was discovered in 1991 when a road was being built in the village, restored to its original appearance in 1997, and officially opened to the public in 2000. As early as in the Western Jin Dynasty, General Liu Kun and Zu Ti stationed a large army here to resist the invasion of Shi Le, a northern Hu ren. At that time, there were numerous tents covering several miles, so the local people named it "Zhangfang" for its similar pronunciation with "accounting tent". The cave entrance at the bottom of the ancient town tower in Zhangfang leads to the underground war passage.