Yanhe is in a valley of the southern bank of Yongding River, and it is over 60 kilometers away from Beijing. The Great Wall which is over 600 kilometers long, is from the east north of Pinggu ,and Miyun, and it goes out in two ways. One is from badaling to Xuanhua and Datong, called outer Great Wall, and the other is from Yanhe town to Zijng Pass and Pingxing Pass along Yanhe Wall and Huangcaoliang, called inner Great Wall.
Yanhe was an important pass of Zijing Pass. At first, it was guarded by Qianhu, then it was guarded by a leading cadre, at last, it was led by the chief army. It is a very important section among the passes in Beijing. Yanhe was built in 16 century AD. The wall’s circumference is 1,100 meters and it is next to Yongding River. It was built depending on the topography and it is like a fan. There are big and small training places, government offices, saint house, Zhen Wu loft and so on. The entire wall is preserved well basically.
The Great Wall goes west from here, passing Huangcaoliang, Valley and Mountain Dongling which is 2,303 meters high. The most remarkable point is the construction ways of the Great Wall are very ingenious, because of the high mountains and dangerous places. Enemy stations and walls interact, so enemy stations control the places, which the Great Wall can’t protect. The important enemy stations have their numbers-from 1 to 16. The ways of construction here are “splitting hill walls” and “dangerous walls”.
Huanghua City lies in the northwest of Huairou, the northeast of tombs of Changping. In Ming Dynasty its east is Mutianyu, and its west is Juyong Pass. It is regarded as the important strategic pass of North Gate of Beijing City. The walls are kept rather well, and are worth of visiting.
Zhangdaokou stretches from Yellow flower to the northwest of Great Wall. It had the closing-door arched door ad the road to walk.