According to the results of the national Great Wall resources survey conducted by cultural relics and surveying and mapping departments, the total length of the Great Wall in Ming Dynasty was 885 1.8km, and it was more than 1 1,000 km in Qin and Han Dynasties and its early period, and the total length was more than 2 1 1,000 km.

The Great Wall starts from Shanhaiguan in the east and ends at Jiayuguan in the west. The total length of the Ming Great Wall is 885 1.8km, of which the artificial Great Wall is 6,259.6km and the trenches and natural disasters are 2,592.2km. ..

Great Wall resources are mainly distributed in Hebei, Beijing, Tianjin, Shanxi, Shaanxi, Gansu, Inner Mongolia, Heilongjiang, Jilin, Liaoning, Shandong, Henan, Qinghai, Ningxia, Xinjiang and other provinces, autonomous regions and municipalities. Shaanxi Province is the province with the richest resources of the Great Wall in China, with a total length of 1838 km.

China's ancient border troubles often came from the north.

Therefore, the role of the Great Wall in past dynasties not only safeguarded national security, but also safeguarded the culture of China. Because the north is flat and the desert is endless, enemy cavalry can be seen everywhere. Therefore, only this continuous fortification can "limit the feet of flax."

But the Great Wall is not only a defense, but also a base for attack. Within the Great Wall, you can train troops, station grain and accumulate all military materials. Without the Great Wall behind it, several military actions since the Qin and Han Dynasties could not get out of the fortress, especially the famous soldiers Wei Qing and Huo Qubing in the period of Emperor Wu of the Han Dynasty. In the future, if the Xiongnu is defeated by Dou Xian in the battle of Jinwei Mountain (Altai Mountain in the northeast of Xinjiang Province) during the reign of Emperor Wu of the Han Dynasty, it will be an unprecedented success.

References:

Baidu encyclopedia-great wall