The ancient structure built in China between the 7th and 16th centuries as a defense is the Great Wall of China. This monumental fortification was constructed to protect against invasions from nomadic tribes and invasions. The wall, which stretches over 13,000 miles, was built with various materials, including earth, wood, bricks, and stone. Throughout its history, the Great Wall also served as a means of border control and trade route protection. It stands today as a UNESCO World Heritage site and a symbol of China's historical strength and architectural ingenuity.