The Great Wall of china isa series of stone and earthen fortification built by a number of emperor to protect the northern borders against nomadic tribe. At one time the wall stretched from Shanhaiguan on China is east coast through a variety of terrines including mountains, plateaus and desert to Lop Nur in the Nort West of the country. Today a lot of that wall has disappeared but parts are still being rediscovered its current length is approximately 4500 miles