The Great Wall, also known as the “10, 000-li (5, 000 kilometer) long Great Wall,” was a complete defensive system consisting of walls, watchtowers, gated passes, and beacon towers. After unifying China in the 3rd century BC, the Qin Dynasty sought to ward off southward incursions of the northern nomadic tribes known as the Xiongnu by linking up and fortifying sections of the defense walls which had been built by the feudal states of Yan, Zhao, and Qin during the Warring States Period that had just ended. Extending about 10, 000 li, the Great Wall wound its way from Lintao in the west (present-day Minxian County, Gansu Province) to Liaodong in the east (present-day Liaoning Province). Later dynasties including the Western and Eastern Han, the Northern Dynasties, and the Sui Dynasty all added sections to the Great Wall in places abutting on northern nomadic tribal areas. The Ming Dynasty was the last Chinese dynasty to engage in extensive construction of the Great Wall, which was rebuilt 18 times between the reigns of emperors Hongwu（1368-1398） and Wanli（1573-1620）. A great part of the Great Wall that still stands today is from the Ming Dynasty. The Ming Great Wall extends from the Jiayu Pass in the west to the Shanhai Pass in the east, with a total length of 8851.8 km. The Great Wall is the greatest defense work built in ancient China. Later the term a “great wall” or a “10, 000-li long great wall” often alludes to a person or a group of people who are a bulwark of the country. This term is also a symbol of fortitude and unity of the Chinese nation.

The First Emperor of the Qin Dynasty then sent General Meng Tian north to build the Great Wall and guard the border. This forced the Xiongnu people to pull back over 700 li, no longer daring to go south to raise their horses… (Jia Yi: On the Shortcomings of the Qin)

As Tian Gui is dead, the country’s great wall has collapsed, and its elite are lost. What should we do? (Chen Chen: Sequel to Outlaws of the Marsh)