The Great Wall", also known as the "Chinese Wall" that was called "The Great Wall Challenge" because it has a length of 6,350 km Great Wall of China built more than 2,500 years before the reign of Qin. The Emperor First Emperor in Chinese History This is to prevent the invasion of the northern tribes. It is constructed by the Emperor in the end of him. The most successful And is one of the seven wonders of the medieval world.