The construction of the Great Wall of China was overseen by several emperors, with the most notable being Emperor Qin Shi Huang, who unified the country in the 3rd century BCE. His reign initiated the first major construction of the Wall as a means to protect against invasions from northern nomadic tribes. Throughout various dynasties, including the Han and Ming, other emperors continued to expand and fortify the Wall, leading to the modern structure we recognize today. The Great Wall is a monument to China's historical struggles, military strategies, and architectural ingenuity.