Great Wall of China the optics much better, rendering photographic evidence irrelevant to the issue of whether it is visible to the naked eye. Great Wall of China The Great Wall of China is a series of fortifications made of stone, brick, tamped earth, wood, and other materials, generally built along an east-to-west line across the historical northern borders of China to protect the Chinese states and empires against the raids and invasions of the various nomadic groups of the Eurasian Steppe with an eye to expansion. Several walls were being built as early as the 7th century BC; these, later joined together and
History of the Great Wall of China Li Zicheng declared himself the founder of the Shun and marched towards the Ming capital from Shaanxi. His route roughly followed the line of the Great Wall, in order to neutralize its heavily fortified garrisons. The crucial defences of Datong, Xuanfu, and Juyong Pass all surrendered without a fight, and the Chongzhen Emperor hanged himself on 25 April as the Shun army entered Beijing. At this point, the largest remaining Ming fighting force in North China was in Shanhai Pass, where the Great Wall meets the Bohai Sea. Its defender Wu Sangui, wedged between the Shun army within and the