The Great Wall is a symbol of China ’s ancient civilization and a testament to construction techniques that have stood the test of centuries.
During the period of the Warring States (476 - 221 BC) the seven kingdoms of Qi, Chu , Yan, Han, Zhao, Wei and Qin built their own city walls to defend their own borders. In 221 BC Qin defeated the other six kingdoms, and the king of the Qin had the city walls linked up and extended to protect the northern territories . It took more than 10 years to complete, and 1 million people, one-fifth of China ’s population at that time, were involved in the project. That completed project was a wall 5,000 km long.
Later, this immense project was expanded to secure the northern territories from Mongol forces. This wall construction was carried out during the Ming Dynasty (1368-1644). The founder of the Ming Dynasty( 1368 - 1644 ) was Zhu Yuanzhang ( 1328 - 1398 ) who sent his General Xu Da( 1332 - 1385 ) to build some sections of the Great Wall. Qi Jiguang ( 1528 - 1588 ) was another influential General who repaired those sections and built some other sections of the Great Wall. The project lasted throughout the Ming Dynasty. Its total length is 6,300 kilometers between Yalu River in the east and Jiayu Pass in the west. This wall is the only man-made structure on earth that can be seen from space.