Tear that wall down....

One of the seven wonders of the world. Can you guess what it is??
















The Great Wall is the world's longest human-made structure, stretching over approximately 6,400 km (4,000 miles) from Shanhaiguan in the east to Lop Nur in the west, along an arc that roughly delineates the southern edge of Inner Mongolia, but stretches to over 6,700 km (4,160 miles) in total. It is also the largest human-made structure ever built in terms of surface area and mass. At its peak the Ming Wall was guarded by more than one million men. It has been estimated that somewhere in the range of 2 to 3 million Chinese died as part of the centuries-long project of building the wall.
http://www.greatwall-of-china.com/