Question: who was the great wall of china built to defend against?
Evidence: Why did he do so? The Qin Empire was threatened by the Huns (the Mongol Empire of the time) in the north. In 215 BC, he sent general Meng Tian to build the Great Wall, using the basis of the northern states' Great Walls to defend against the Huns.
Answer: nomads from Inner Asia
nomads from Inner Asia .