The Great Wall of China was primarily constructed to protect the Chinese states from invasions by nomadic tribes, particularly from the north. It served as a military defense system, encompassing watchtowers and fortifications for detecting and repelling invaders. Additionally, the wall helped regulate trade along the Silk Road, providing a protective barrier for merchants. It also symbolized the strength and unity of the Chinese people, demonstrating the lengths they were willing to go to safeguard their territory and maintain control over their borders. Thus, the Great Wall became both a physical barrier and a cultural icon.