Of course, the Wall of China required a lot of man labour. During the First Empire, the army (which numbered about 300 000 soldiers) was summoned. The Qi Dynasty enlisted nearly two million men. The construction works being too slow, some convicts were forced to work on the building site; but this help was still not enough, therefore, the population was obliged to work as well. At that time, the safety conditions were terrible; hundreds of thousands of men died of hunger or of exhaustion. A Chinese ballad relates these facts: “If your child is a girl, you must drown her. If your child is a boy, you mustn’t rear him. Don’t you see that the Great Wall is building itself on dead bodies? ” A number of dead bodies were buried in the surrounding of the wall. Low relieves pay a tribute to those slaves. An estimated ten million men died. 209 BC (one year after Qin Shi Huangdi’s death) the first and most violent peasant revolt in China’s history broke out.

   The curves of the Great Wall tried to take as much advantage as possible of the natural obstacles. The Ming building is mostly set up around a mountain, for a better protection. Beyond its defensive function of prime importance, in the facts, the Great Wall has played different roles. The growth of the Silk Route benefited from the protection of the wall, since 200 BC. Besides, the arrival of the colonists and the economic weight of the stations helped a lot in the development of a northern region weakly populated and economically behind the others, such as the rich southern plains. The Great Wall gave a chance to the peasants to break uncultivated land and to protect them, to exploit production in the areas along the border. The circulation of the products and the station’s relief allowed a stirring of the products and also mixed the different Chinese cultures. Those major impacts can compare to an unequalled structure which sheltered more than one million warriors under the Ming Dynasty. The Great Wall was also used as an artistic, political and religious support. Many different stone engravings can be seen on the walls.

   Of course, the Great Wall was never totally effective and has not pushed back determined invaders. Thus, the invasion of Northern China, 200-300 BC by the Turco-Mongol troops wasn’t prevented. Neither was the occupation of Beijing by Genghis Khan’s troops in 1215, and later, again by the Mongols in1552. Finally, tribes from oriental Mongolia, after having subdued Manchuria and then all of China chasing out the Ming to create the Qing Dynasty, will outline once again and for the last time the fact that China couldn’t only rely on the Great Wall to protect itself.