China has a long history, dating back to the Spring and Autumn Period and the Warring States Period. In order to defend each other, vassal States built defensive walls in their respective jurisdictions, which is the prototype of the Great Wall. According to Zuo Zhuan, in 656 BC (the 16th year of King Chu), the Great Wall stretching for hundreds of miles was built in the State of Chu. It was called Fangcheng at that time. The city is strong and easy to defend but difficult to attack. As a result, the leaders of Qi who came to invade were frightened and had to retreat.
Qin Changcheng was built in the 3rd century BC and has a long history of more than 2,300 years. If traced back to the Chu-Qi Great Wall in the late Western Zhou Dynasty and the Spring and Autumn Period and the Warring States Period, the Great Wall in China has a history of at least 2,700 years. Even the Great Wall built in the Ming Dynasty is more than 600 years old. It is very rare, precious and rare that such an ancient and great building can be preserved so far in the world.
The length is amazing. According to the investigation and statistics of relevant departments, from the Spring and Autumn Period and the Warring States Period to the Ming Dynasty (including a few political powers in the Central Plains), the Great Wall was maintained and added to varying degrees in past dynasties. The Great Wall spans 65,438+06 provinces, municipalities and autonomous regions in the Yellow River and the Yangtze River valley, with a total length of 65,438+008,000 Li (54,000 km) in the east-west and north-south directions. Among them, Qin Changcheng, Han Great Wall and Ming Great Wall are all more than one Wan Li. Because it is more than Wan Li, it is called the Great Wall of Wan Li.
Badaling Great Wall, built in Ming Dynasty, is the youngest, grandest and best-preserved section of the Great Wall in China. It starts from Yalu River in Liaoning in the east and ends at Jiayuguan in Gansu in the west, spanning nine provinces, municipalities directly under the Central Government and autonomous regions of Liaoning, Hebei, Tianjin, Beijing, Inner Mongolia, Shanxi, Shaanxi, Ningxia and Gansu. Total length 12700 Li (6350 km). Among them, the section from Yalu River to Shanhaiguan has already collapsed because of the relatively simple project, but there are traces to be found. From Shanhaiguan to Jiayuguan, the engineering quality is the best, and most of them are well preserved. Some people mistakenly believe that the Great Wall of Ming Dynasty originated in Shanhaiguan, mainly for the above reasons.
According to scientists' rough calculation, if a wall with a width of 3 feet and a height of 15 feet is built from the soil, bricks and stones of the Great Wall in the Ming Dynasty, it can circle the earth. If it is used to pave a road with a thickness of one foot and a width of 15 foot, it can circle the earth three times.
The Wan Li Great Wall passes through places with superb buildings, or mountains and deep valleys, or rivers and lakes, or desert grasslands. The geological terrain is extremely complex and steep and the construction is particularly difficult. To build the Great Wall, we must understand and apply scientific and technical knowledge such as mathematics, mechanics, geometry, surveying, geology, architecture, histology, transportation and so on. The working people in ancient China were able to build this huge and complicated project and stand for thousands of years, which shows that the infinite wisdom and great creative spirit of the Chinese nation are convincing and eulogizing.