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
Great Wall of China Beyond Jiumenkou, an offshoot known as the Liaodong Wall continues through Liaoning province and terminates at the Hushan Great Wall, in the city of Dandong near the North Korean border. In 2009, 180 km of previously unknown sections of the wall concealed by hills, trenches and rivers were discovered with the help of infrared range finders and GPS devices. In March and April 2015 nine sections with a total length of more than , believed to be part of the Great Wall, were discovered along the border of Ningxia autonomous region and Gansu province. Before the use of bricks, the