The Great Wall of China is one of the greatest wonders of the world. It winds up and down across deserts, grasslands, mountains, and plateaus. It stretches approximately 13,170 miles from east to west of China. With the history of more than 2,000 years, some of the sections are now in ruins or have disappeared. However, the Great Wall of China, is still one of the most appealing attractions all around the world.
Great Wall was originally built in the Spring and Autumn, and Warring States Periods as a defensive fortification. It went through constant extensions and repairs in later dynasties. It began as independent walls for different states when it was first built, and did not become the "Great" wall until the Qin Dynasty. Emperor Qin Succeeded his effort to have the walls joined together to fend off invasions. Since then, the wall has served as a monument of the Chinese nation throughout history.
Before the use of bricks, the Great Wall was mainly built from rammed earth, stones, and wood. During the Ming, however, bricks were heavily used in many areas of the wall, as were materials such as tiles, lime, and stone. The size and weight of the bricks made them easier to work with than earth and stone, so construction quickened. Additionally, bricks could bear more weight and endure better than rammed earth. Stone can hold under its own weight better than brick, but is more difficult to use. Consequently, stones cut in rectangular shapes were used for the foundation, inner and outer brims, and gateways of the wall. Battlements line the uppermost portion of the vast majority of the wall, with defensive gaps a little over 30 cm tall, and about 23 cm wide. From the parapets, guards could survey the surrounding land. Communication between the army units along the length of the Great Wall, including the ability to call reinforcements and warn garrisons of enemy movements, was of high importance. Signal towers were built upon hill tops or other high points along the wall for their visibility. Wooden gates could be used as a trap against those going through. Barracks, stables, and armories were built near the wall's inner surface.
Great Wall carries a considerable part of Chinese culture. It 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 Jiangnu, who cried bitterly over the death of her husband after he died while building the wall. This legend has been spread widely through textbooks, folk songs and traditional operas.
Following a 45-day long survey of 101 sections of the Wall in different provinces, the China Great Wall Academy reported on December 12, 2002 that the forces of nature and destruction by mankind are bringing about gradual reduction of extent of the Wall. With the result that less than 30% remains in good condition. The Academy has called for greater protection of this important relic.
The Great Wall stretches from Dandong in the east to Lop Lake in the west, along an arc that roughly delineates the southern edge of Inner Mongolia. A comprehensive archaeological survey, using advanced technologies, has concluded that the Ming walls measure 8,850 km. This is made up of 6,259 km sections of actual wall, 359 km of trenches and 2,232 km of natural defensive barriers such as hills and rivers. Another archaeological survey found that the entire wall with all of its branches measure out to be 21,196 km.