Great wall is the most recognizable symbol of China. Today The remains of the great wall could be seen in over 15 provinces throughout china . These walls were built in different dynasties over a period of 2700 years.
Chinese people used to say "wan li chang cheng", which means the great wall of 5000 kilometers long, but that only means the great wall built in Qin dynasty. According to a recent research made by Chinese government, the full length of great wall in China is more than 21,000 kilometers.
The beginning of the Great Wall of China can be traced to Spring and Autumn period as early as 7 century BC. As Zhou dynasty fall, China was divided into a number of individual kingdoms, they fought each other and built up walls on the border for protection.
Until 221 BC, when Qin defeated all the rivals and unified China, The first emperor of China, Qin shi huang, ordered that earlier fortifications between states be removed and a number of existing walls along the northern border be joined into a single system that would extend for more than 5000km and protect China against attacks from the north.
The famous Chinese general Meng Tian directed the project, and was said to have used a million of soldiers, convicts and commoners as workers. as many as 400,000 people died during the wall's construction; many of these workers were buried within the wall itself. the wall stretched from the China Sea port of Shanhaiguan over 5000km west into Gansu province.
After Qin dynasty, China come into a circle of splits and reunifications. Once the country was unified the ruler will inevitably repair great wall or built up new wall for safety.
In early Han dynasty, China was facing attacks from barbaric Huns, Emperor wudi, sent general Huoqubin and weiqing defeated Huns on Mongol plateau and in the Hexi corridor. In order to block the Huns from coming into China and protect the newly claimed land – Hexi Corridor, the emperor ordered soldiers to built up the great wall from Linju to Lop nor (the west of Yumen pass) and repaired the great wall built in Qin dynasty. So the great wall of the Han dynasty start in the east of Liaonin Province extended westward to Lopnor in Xinjiang, totally more than 10,000km.
The great wall most tourists visit and seen was built mainly in the Ming Dynasty (1368 – 1644).
To prevent a comeback of the Yuan Dynasty (1279-1368) and to keep the Nuzhen tribes out, Ming began to rebuild and extend the walls constructed by the previous dynasties soon after it came into power. This project took more than 100 years and the laborers and resources involved were phenomenal.
The wall of Ming Dynasty winds from Jiayuguan in the west to Liaoning Province in the east, across 9 provinces, measuring around 8,851 kilometers long. This wall traversed mountainous terrains and conformed to the territories' numerous peaks and valleys.
The Great Wall of Ming Dynasty is the most outstanding project with the longest time, grandest scale and most complete and solid defense systems as well as structures. It highlights the extraordinary architecture skills at that time and contributes a lot to guide the border against invasion, to facilitate the trade along the Silk Road and to develop the western area of China.
During the 270 years of Ming Dynasty, the construction of the Great Wall never ceased, different from the Great Wall of Spring and Autumn Era or Qin dynasty, the Great Wall of Ming Dynasty is the upgraded version which comprises walls, passes, watch towers, troop barracks, garrison stations, signaling capabilities.
Why only Chinese people build walls for protection?
The most convincing answer is geography. Chinese civilization originated in fertile central plain along yellow and Yangzi river. Due to the natural advantage, Chinese people made prominent strides in ancient agricultural technology. If you look at China’s geography , you will find that China’s terrain is largely flat, making the country extremely vulnerable to foreign invaders, but the land of china was protected by Tibetan Plateau to the west, Himalayas to south and pacific ocean to the east. Only north and northwest is open wide.
Compared to China’s fertile land, the central and northern Asia were mostly just arid plains, so the inhabitants of these lands never even had the option to simply settle down. Instead, they were forced to pursue the pastoral life. It comes as no surprise that the nomadic tribes of these regions found it preferable to attack the prosperous lands of China instead! So Chinese people need to build up walls on northern border, where there is no natural barrier as protection.
Materials used for construction.
The materials used are those available near the wall itself. Near Beijing the wall is constructed from quarried limestone blocks. In other locations it may be quarried granite or fired brick. Where such materials are used, two finished walls are erected with packed earth and rubble fill placed in between with a final paving to form a single unit. In some areas the blocks were cemented with a mixture of sticky rice and egg whites.