The Great Wall of China

The Great Wall of China is one of the Seven Wonders of the World and stretches 6000 km, forming a boundary between China and barbarian tribes to the north. Construction on the wall started in 5th century BC and continued for a thousand years until the 16th century. The wall is seven meters high and seven meters thick, with around 25,000 battlements. While walled cities were common in China, it wasn't until Qin Shi Huang that a unified border was erected to safeguard the empire. According to astronauts who looked back from the moon, of all projects built by man, the Great Wall of China is the most conspicuous visible from space.

History of Great Wall

The construction of the Great Wall started in the 7th century B.C. According to records found in the existing Chinese literature, almost 20 principalities and dynasties took part in reconstructing the Great Wall. The Great Wall was originally built as a defensive fortification in the spring, autumn, and Warring States Periods. For self-protection, rival kingdoms built walls around their territories, laying foundations for the present Great Wall. The Great Wall went through constant extensions and repairs in later dynasties. In fact, it began as independent walls for different states when it was first built, and did not become the "Great" wall until the Qin Dynasty.

The first emperor Qin Shihuang unified China in 221 B.C., eventually the walls was joined together to hold off the invaders from the Xiongnu tribes in the north and was extended to more than or 5,000 kilometers. The construction of such a huge project over difficult terrain at that time without any machinery was an extraordinary feat. A workforce of nearly a million, some of the laborers could not bear the hardship and the cruel treatment and therefore many laborers of them died. After the Qin Dynasty the renovation process kept moving from time to time.

During the Han Dynasty the Great Wall of China was continuously built. With its system of fortifications and beacon towers, the Han Great Wall reached a total length of about 10,000 kilometers.

The Great Wall ceased its function for almost 300 hundred years with the expansion of the Tang Empire (618-907AD) as the frontier was pushed further north. Ince the Han and various other dynasties, rebuilt the Great Wall on extensive scale. The engineering projects undertaken in the Ming dynasties were the largest.