As the western starting point of Jinshanling Great Wall, the Longyukou section was a glaring weakness in the Wall. Here, due to the low slopes that make it easier to attack than to defend, the Wall here is thicker and sturdier than sections in other places.

Beacon towers were important military buildings in Chinese history. Various types of beacon fires were adopted according to different situations. Using this system, the warning of enemy arrival could be passed from the border to the interior—nearly one thousand kilometers away—in just one day. The beacon tower in the photo stands in the Balikun area of Xinjiang, guarding the vital path of the ancient Silk Road. There are still dozens of such constructions scattered within this  area. Photo/ Chen Zhiyong

Among all the sections of the Great Wall, the one in Hebei Province especially stands out because it is unique both in terms of its construction standards and in its defensive capability. The Yanglai Watchtower of Banchangyu Great Wall in Funing County, Qinhuangdao was constructed during the Wanli Era (1573–1620). This hollow watchtower was elaborately designed and well-preserved, and has a complex structure with comprehensive functions. Due to the windows for firing arrows on its four sides, it is also called the Four-eye Watchtower. Photo/ Yang Yueluan

In Banchangyu Village, the Great Wall winds along the ridge of the Xishanling Mountains. The well-preserved Wall is distinguished by its single-sided flank wall structure, beyond which is a sheer precipice that made approaching the Wall a painstaking endeavor.  Photo/ Xu Meixia 

In a small village named Xigou in Suizhong County, Liaoning Province, a dilapidated watchtower stands on a bleak mountaintop, overgrown with grass that accelerate its distruction. A herd of goats graze around it, adding some rare cheerfulness to the ancient and lifeless Great Wall. Countless sections of Great Wall suffers the same fate, dying alone and silently in isolated rural areas, becoming nothing but a pile of rubbles. Photo/ Wang Ximing