THE GREAT WALL OF CHINA

The Great Wall of China, whose building started more than 2000 years ago, represents a main part of Chinese history, which has a profound influence on china today.It is the world's longest and largest human-made structure, stretching over approximately 8,851.8km, across the mountains of northern China, winding north and northwest of Beijing. The Great Wall is a series of stone and earthen fortifications in, built, rebuilt and maintained between the 5th century BC and the16th century AD to protect the northern borders of the Chinese Empire during the rule of successive dynasties.In Chinese the wall is called "Wan -Li Qang-Qeng", which means 10,000-Li Long Wall (10,000 Li = about 5,000km).

The purpose of the Great Wall was to protect China from outside aggression, but also to preserve its culture from the customs of foreigners. The Wall was originally built in the Spring and Autumn, and Warring States Periods as a defensive fortification by the three states: Yan, Zhao and Qin. It went through constant extensions and repairs in later dynasties.It began as independent walls for different states when it was first built and became the "Great Wall" when the Qin Dynasty Emperor Qin Shihuang succeeded in his effort to have the walls joined together to fend off the invasions from the Huns in the north.The Great Wall we see today was mostly built during the Ming Dynasty (1368-1644).It starts from Hushan Great Wall in the east to Jiayuguan Pass in the west traversing Liaoning, Hebei, Beijing, Tianjin, Shanxi, Inner Mongolia, Ningxia, Shaanxi, Gansu and Qinghai.

The mystery of the construction of the wall is amazing. The construction ,which drew heavily on the local resources for construction materials, was carried out in-line with the local  conditions under the management of contract and responsibility system. A great army of manpower, composed of soldiers, prisoners and local people, built the wall.The wall was originally built of stone, wood,grass and earth. In the Ming Dynasty, bricks were produced in kilns set up along the wall.The bricks were transported by men carrying them on their backs, donkeys,mules and even goats had a brick tied to their head before being driven up a mountain.The Great wall demonstrates the wisdom and tenacity of the Chinese people.

Great Wall of China from space,taken by Proba on march 25

One of the famous myth about the Great Wall is that it is visible to the unaided eye from the moon, whose average distance from Earth is 384,393km.The wall is a maximum 9.1m   wide, and is about the same color as the soil surrounding it.The apparent width of the Great Wall from the moon is the same as that of a human hair viewed from 3.2km away.To see the wall from the moon would require spatial resolution 17,000 times better than normal vision.So, no lunar astronaut has ever claimed to have seen the Great Wall from the moon.And NASA claims that it is barely visible from low earth orbit, and only under nearly perfect conditions; it is no more conspicuous than many other man-made objects.

The Great Wall also has long been incorporated into Chinese mythology and symbolism. The most well-known legend is about the collapse of a section of the wall caused by Meng Jiangan who cried bitterly over the death of her husband after he died while building the wall.

The Great Wall of China was listed as a World Heritage by UNESCO in 1987.Some of its sections are now in ruins or have disappeared, however, it is still one of the greatest wonders of the world and most appealing attractions all around the world owing to its architectural grandeur and historical significance.