The Great Wall of China Is Coming Down

 From History of Yesterday:

The building of the wall started during the 7th century BCE by the ancient Chinese state known as Chu which ruled during 770–223 BCE. When the state was formed, its leaders wanted to build a new type of defensive system that would not only protect a village or a simple settlement but a whole region without the need for a large army. It is believed that this was the first time someone in human history had thought of using walls to create borders. Therefore they started building a large fortified wall around the whole prominence of Hubei, with guard posts every 10 kilometers.

During the 6th century, other states within China soon followed this tactic. They all understood that this would help defend their own regions from their neighbors throwing a surprise attack. Another vital point of building the great wall was to protect China from nomadic tribes that attempted raids and invasions from the north. Until the 2nd century BCE, all the sections of the walls were separate, not connected from one region to another. (Read more.)