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 the east. This section was one of the first to be renovated following the turmoil of the Cultural Revolution. At the edge of the Bohai Gulf is Shanhai Pass, considered the traditional end of the Great Wall and the "First Pass Under Heaven". The part of the wall inside Shanhai Pass that meets the sea is named the "Old Dragon Head". north of Shanhai Pass is Jiaoshan Great Wall (焦山長城), the site of the first mountain of the Great Wall. northeast from Shanhaiguan is Jiumenkou "Jiǔménkǒu"), which is the only portion of the wall that was built as a bridge.