만리장성, or the Great Wall of China, is a series of fortifications built to protect Chinese states from invasions. Construction began in the 7th century BC and continued for centuries, with the most famous sections built during the Ming Dynasty (1368-1644). The wall stretches over 13,000 miles across northern China. The wall is made from various materials, including earth, wood, bricks, and stone. It features watchtowers and barracks for soldiers. Today, 만리장성 is a UNESCO World Heritage Site and a popular tourist destination, symbolizing China's historical strength and architectural ingenuity.