T he Great Wall refers to a huge military project against intrusions by northern nomadic groups in different periods in ancient China. It stretches for over 10,000 km from east to west, so it is also called The Long Wall of Ten Thousand Kilometers. As an ancient defense project that required the longest time of construction and the biggest workload in the world, it was built during the Spring and Autumn period and the subsequent Warring States period over 2,000 years ago. The existing relics of the Great Wall are mainly the Great Wall of the Ming Dynasty built in the 14th century. According to data issued by the State Administration of Cultural Heritage in 2012, the total length of the Great Wall in past dynasties is 21,196.18 km; the State Administration of Cultural Heritage published data on the Great Wall of the Ming Dynasty in 2009, indicating its total length of 8,851.8 km. The Great Wall is a great miracle created by ancient working people of China and is the witness of China’s long history. Moreover, it is one of eight wonders of the world together with other wonders like Colosseum of Roman, Leaning Tower of Pisa and Pyramids of Egypt. In December 1987, the Great Wall was listed as a world cultural heritage.