The Great Wall of China is about 21,196 kilometers long great wall in China. This great wall was built east-to-west to form a united defence system against invasions from the north. It begins in the east at Shanhaiguan in Hebei province and ends at Jiayuguan in Gansu province to the west.
The Great Wall of China was continuously built from the 3rd century BC to the 17th century AD. Its main body consists of walls, horse tracks, watch towers, and shelters on the wall, and includes fortresses and passes along the Wall. The Great Wall of China is the only work built by human hands on this planet that can be seen from the moon. It was designated as a UNESCO World Heritage Site in 1987.