The ancient civilization credited with building the Great Wall of China is the Qin Dynasty, which reigned from 221 to 206 BCE. This monumental construction was initiated by Emperor Qin Shi Huang, who sought to unify various walls constructed by earlier states into a single defensive barrier to protect against invasions from northern tribes. Over the centuries, various dynasties, including the Ming Dynasty, expanded and renovated the Wall, incorporating advanced architectural techniques. The Great Wall today symbolizes China's historical strength and the ingenuity of its people, as well as serving as a UNESCO World Heritage Site and a major cultural landmark.