Did the Great Wall of China Work?
A powerful military defense project
As early as 7th century BC, the state of Chu began to build the Great Wall in order to resist the threat of northern nomadic people. Although the Great Wall measured approximately 3 - 4 meters (3.3 - 4.4 yards) high at that time, it still managed to delay the assault of the nomads. After Emperor Qin Shihuang unified China, he joined the separate Great Wall sections built by previous states to form a huge complicated frontier defence, resisting the invasion of the northern Huns and consolidating his rule. The Great Wall was also extended during the Han Dynasty (202 BC - 220 AD) and continued to protect the land from invasion during most of later dynasties. The Silk Road, an international trading route extending from Xi’an to European countries also found protection within the Great Wall's defence.
Historically, the Qin (221 - 207 BC), Han and Ming (1368 - 1644 AD) dynasties were the most frequently invaded by the northern nomads while being the most active dynasties in the construction of the Great Wall.
The Great Wall of China was a functional military defense system and oversaw a ray of functions including messages and combat strategies.
Delivering messages: The soldiers stationed at the beacon towers transmitted messages by fire or smoke to warn their troops once the enemy was seen approaching.
Defending: The Great Wall is generally located in high terrain, like a military screen to defend the people inside.
Transporting troops and supplies: The wide passages on the top of the wall are beneficial to troop’s movement and supplies’ delivered during battles.
Aggressing and Territory Expansion: Chinese troops relied on the Great Wall to attack the Huns. If they won, they kept advancing and took over the territory of the nomads; if they lost, they returned and sought defense from the Great Wall.
Some sucesses, some failures
In the face of attack, the Great Wall helped organize defense and reduce the losses caused by nomadic people from the north. In the era of cold weapons, it certainly worked well. During the 2,000 years' stretching from the Qin Dynasty to the Qing Dynasty (1644 - 1911 AD), there was only one person - Genghis Khan who broke through it.
See more Genghis Khan breached China Great Wall
During the middle and late Ming Dynasty, gunpowder was introducted to the military. The Great Wall defense gradually weakened and after the 19 century, the Great Wall ceased serving as military defense project. Nowdays, the Great Wall enjoys being a popular tourist attraction and a cultural symbol of the Chinese nation.