The construction of the wall began during the Spring and Autumn period(770一476 BC)and the Warring States period(475一22l BC). To consolidate the country and ward off invasion by ethnic minority tribes in the north，First Emperor of Qin had the walls linked and extended，giving rise to the 5 000-kilometer- long Qin Great Wall. Later dynasties from Han(206 BC一220 AD)to Ming( 1368- 1644) kept building and improving the wall，extending it more than 1 000 kilometers to today’s scale. The Great Wall starts from Qin Huangdao City,Hebei province in the east ，and ends at Jiayuguan City , Gansu Province in the west. The wall stretches across the vast area of north and central China reputed as“Enlivened for 2 000 years and Maneuvering for 100 000 Ii”. From east to west the sections at Shanhaiguan, Jinshanling, Mutianyu，Badaling and Jiayuguan have become tourist attraction.
The best preserved and most imposing section is at Badaling in Beijing. The section，located outside the Juyongguan Pass, is made of large blue bricks and has an average height of 7. 8 meters. Five to six horses can be ridden abreast along it. At regular intervals there is an arched door leading to the top of the wall. The walls are covered with many lookout holes，window embrasures and castellated crenels. Beacon towers were also built at fixed intervals for passing on military information. All these indicate the important role of the Great Wall in military defense. Badaling Great Wall represents the magnificent and precipitous features of the Great Wall. As a barrier to Beijing, the mountains overlap and the situation is critical. The two characters of “natural danger” written by the ancients on the precipice of the Great Wall, which is unfolded on both sides of the mountain, accurately summarizes the military importance of Badaling
Outside the east gate of Badaling pass, there is a piece of natural granite with a height of 1 meter and a length of 15 meters, engraved with the words “wangjingshi”.
Located in the inner side of Dongguan gate, there are two characters of “natural danger”on a chiseled flat cliff, inscribed in 1835 (the 15th year of Daoguang in Qing Dynasty).
There are five iron cannons beside the horse road at the entrance of Badaling, which is one of the advanced weapons at that time. Among them, the largest gun barrel is 2.85 meters long, with a range of more than kilometers, which is very powerful. It was made in 1638 in Chongzhen years of Ming Dynasty. The other four small cannons were unearthed during the renovation of the Great Wall in 1957. At the same time, hundreds of shells were unearthed, they were all Ming Dynasty’s products.
There is a temple outside the east gate of Badaling, whichnamed Wangjing Temple. Inside, there is a statue of great compassion Buddha carved from stone and rock. Outside the west gate, there is a memorial archway with the inscription “Drive away the Hu people for ten thousand li”.
Badaling Great Wall has a total of 43 enemy buildings, which are similar in shape and have their own characteristics. Among them, there are wall platforms for patrolling and sentry duty, as well as two enemy platforms, the upper layer is surrounded by crenels and shooting holes, and the lower layer is houses for soldiers’ accommodation and storage of materials.
From Guancheng to the fourth building in the south, the wall is 685.8 meters long and 127 meters high, with an average rise of 1 meter every 6 meters. Between the third buildingg and the fourth building, the mountain is steep, the wall is about 500 meters, and the most dangerous place has a slope of 70 degrees. The fifth building in the north is the enemy building with the most holes. The building is 9.25m long and 9.34m wide, with two upper and lower floors. Entering the first floor from the arched door, there are many arched holes, four rows of brick stacks on each side, and each stack is arched with an arched top. There are more than 30 coupon holes supporting the ground of the second floor. The sixth building in the north. The largest enemy building. The building is 12.6 meters long and 8.5 meters wide. The ground floor area is about 100 square meters. There are 7 rows of brick stacks on the long side and 4 rows of brick stacks on the wide side. The top of the stack issues vouchers, forming a square corridor shaped voucher path, leaving space in the middle, forming a rectangular patio. You can climb the stairs from the patio to the top of the building.The North eighth building, with an altitude of 888 meters, is the highest enemy tower of Badaling Great Wall, which is the best place to overlook the Great Wall, so it is also known as the sun watching platform. There are two floors in the building with stairs
Pier is also called beacon tower. There is a pier in the East and a pier in the west of Badaling Great Wall. On the piers and abutments, there are suspended buildings and timber bases, under which there are moats and suspension bridges, and around which there are collapsed cellars. Soldiers use rope ladders to go up and down without building steps. Each set has two fire guns and two guns, and 10 guards. It is defended by the nearby Castle Garrison and forms a defense network in depth with the castle
Chengtai is slightly higher than the top of the Great Wall, surrounded by battlements, crenels, shooting holes and other platform buildings. This is the place where ancient soldiers patrolled and defended in case of war. For example, the platform at the top of the gate of Badaling pass is Chnegtai.
The platform cannons are built in the important traffic roads or dangerous places along the Great Wall. They are blockhouse buildings, with one, two or three floors and different scales. It can store weapons, ammunition and other strategic materials inside, and its effect is greater than that of enemy buildings. In addition, there are arrows, iron bars, thousands of stones on the platform, as well as a month’s rations and water reserves. It can not only attack, but also defend. It can cooperate closely with the military facilities on the Great Wall, such as Chengtai and enemy tower, to form a dense fire network, greatly enhance the combat power, effectively block the enemy’s attack, and play a very important strategic and tactical role in military defense.
As one of the most magnificent ancient defense works, the Great Wall is known as one of the wonders of the world. All tourists now know the saying，”You are not a real person until you have climbed the Great Wall.”