Explanation : The Great Wall of China was mainly built during the reign of Emperor Qin Shi Huang, along the country’s northern border to prevent the invasion of Huns, Qin Shi Huangwas the founder of the Qin (Chin) dynasty and was the first emperor of a unified China in 221 B.C. Later the Han (202 B.C-220 A.D), the Northern Qi (550-574), the Sui (589-618), and particularly the Ming (1369-1644) were among those that rebuilt, re-manned, and expanded the Walls. ....Read more