The Great Wall of China actually consists of numerous walls and fortifications. It was originally conceived by Emperor Qin Shi Huang (ca. 259–210 BC) in the third century BC as a means of keeping out the Mongol hordes invading the country. The best-known and best-preserved section of the Great Wall was built in the 14th through 17th centuries, during the Ming dynasty (1368–1644). Though the Great Wall never effectively prevented invaders from entering China, it’s still a massive engineering and construction feat and human accomplishment.