There are historical materials about the Great Wall.

The Great Wall is an ancient defense project with the longest construction time and the largest engineering quantity in China and even in the world. Since the Western Zhou Dynasty, it has been built continuously for more than 2,000 years, distributed in the vast land in northern and central China, with a total length of more than 50,000 kilometers.

Since Qin Shihuang, almost all dynasties that ruled the Central Plains have built the Great Wall. There are more than ten dynasties such as Han, Jin, Northern Wei, Eastern Wei, Western Wei, Northern Qi, Northern Zhou, Sui, Tang, Song, Liao, Jin, Yuan, Ming and Qing, all of which have built the Great Wall of different scales.

The Great Wall is an ancient military defense project in China. It is a tall, solid and continuous long wall, which is used to limit the enemy's riding. The Great Wall is not a simple isolated wall, but a defense system with the wall as the main body and a large number of cities, obstacles, pavilions and landmarks.

Extend the representative sections of the Great Wall of Information:

Shanhaiguan 1

Shanhaiguan, known as "the first pass in the world", is located at the northeast of Qinhuangdao 15km, where the Great Wall of Wan Li enters the sea. The total length is 26 kilometers, including: Laolongtou Great Wall, Guancheng Great Wall in the south wing, Jiao Shan Great Wall in the north wing, Sandaoguan Great Wall and Jiumenkou Great Wall. Laolongtou Great Wall is the end part of the Great Wall entering the sea.

Shanhaiguan was the product of the garrison system established in Ming dynasty, and the "reclamation system" and reform policy of Ming dynasty played an important role in the consolidation and development of Shanhaiguan.

2. Zhenbeitai

Zhenbeitai is located in Yulin City, Shaanxi Province, a famous historical and cultural city, about 3 kilometers away from the urban area. Built in the thirty-fifth year of Wanli in the Ming Dynasty (1607), it is the most magnificent building in the Great Wall of Wan Li.

It is also the most magnificent military fortress and observation post on the Great Wall of Wan Li. Known as "one of the three wonders" of the Great Wall of China (Shanhaiguan in the east, Zhenbeitai in the middle and Jiayuguan in the west), it is "the best in the world". According to the danger, it is square, ***4 floors, more than 30 meters high and covers an area of 5056 square meters.

3. Jiayuguan Great Wall

Jiayuguan Great Wall is located in the southwest corner of Jiayuguan City, Gansu Province. It was named after it was built at the foot of Jiayu Mountain. It is the starting point of the western end of the Ming Great Wall. It was built in the fifth year of Hongwu in Ming Dynasty (1372). It is the most well-preserved Chengguan along the Great Wall in the Ming Dynasty, the first pass in Hexi and an important stop on the Silk Road.

Chengguan is a complete defense system composed of inner city, outer city and moat. Rammed by loess and covered with city bricks, it is solid and majestic. The Guancheng plane is trapezoidal, covering an area of more than 33,500 square meters, with a total length of 733 meters and a height of 1 1.7 meters.

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