Shanhaiguan is one of the major passes of the Great Wall and is located near the city of Qinhuangdao. Shanhaiguan is rectangular in shape with a perimeter of four kilometers. The walls reach a height of 14 meters and are seven meters thick. The east, south, and north sides are surrounded by a deep and wide moat. In the center of the rectangular area stands a tall bell tower. Above the east gate of the structure is a plaque with the inscription "First Pass under Heaven." Five kilometers east of Shanhaiguan lies the end of the Great Wall, known as the Old Dragon's Head, where the Great Wall emerges from the sea.
http://www.china.org.cn/olympics/host_cities/2007-07/31/content_1218514.htm
