The Great Chinese Wall, one of the great wonders of the world, lies like a huge dragon passing through dessert,plains and high mountains having a combined lenght of aproximately 6700 kilometers from the east to west of China. With a history of over 2000 years, some portions of the wall are now in ruins, while some have entirely disappeared.Nobody knows exactly when contruction of the Great Chinese wall started, but it is believed that originally it was built with the purpose of defense against the tribes, during the Zhou Dynasty. Later between 770 and 476 B.C. it was perfected by the emperors Yan, Zhao and Qin for the same purpose of defense. Intialy the Great Wall was built in pieces as protection walls for each separate state and only during the Quin dynasty the emperor unified the wall after the unification of China to protect against the invading huns in the north. The wall was further lenghtened and strengthened during the next dynasties, especially during the Ming dynasty.Being built in a long period of time, the great Chinese wall has many sections built from different materials. Before using bricks the Great Wall was built in large part from earth, stone and wood. Due to the fact that it took huge amounts of materials to build the wall, builders have tried to exploit local materials. In the mountains rock was the main material used, in the plains they used earth and in the desert they even used the poor vegetation they could find (sand reed) and bind it whith earth.The Great Wall was built with the help of millions of people: during the Qin Dynasty, a period of 10 years 300000 people of general Meng Tian were used. Later during the Qi Dynasty a section of 450 km was built with the aid of 1.8 million people. Because of the extremely heavy labor many workers have found the end there, manny of them even being buried in the walls of the building. The emperor Qi found a very engenious and sadistic way to get more workers to the wall. He used convicts to build the wall and the rule was that if a convict died before his sentece expired a family memeber had to take his place until the sentence had been exausted. This gave the building supervisors the means to push convicts as hard as they wanted because if they commited suicide a family member was brought in they’re place. This draticaly reduced the criminality in China so many soldiers where also used tu build the wall.The Wall was not only build as a protection agains the tribes but it was also designed that if atacked soldiers on the wall could signal troups garrisoned far away in a matter of minutes. The wall is mainly composed of passages, walls and observation towers located at key high points. If the wall was atacked a fire was lighted on top of the towers and soldiers where imediately dispatced to that point.In the begining of the XIX th century the wall was abandonded until 1952 when it was declared by the Chinese government a historical monument.Nowadays the Great Wall sufferes of excesive tourism and because of the lenght of the wall and lack of funds manny portions of the wall are completely ruined. The wall in a relatively natural condition can be seen at Simatai, 110 km northeast of Beijing. This part of the wall is still in its original state, not turned into a popular tourist attraction, due to distance and few transportation options.