The Great Wall of China,also known in China as the Great Wall of 10,000,is an ancient Chinese fortification built from the end of the 14th century until the beginning of the 17th century,during the Ming Dynasty,in order to protect China from raids by the Mongols and Turkic tribes.It was preceded by several walls built since the 3rd century BC against the raids of nomadic tribes coming from areas now in modern day Mongolia and Manchuria.The Wall stretches over a formidable 6,350 km (3,946 miles),from Shanhai Pass on the Bohai Gulf in the east,at the limit between China proper and Manchuria,to Lop Nur in the southeastern portion of Xinjiang Uygur Autonomous Region.