美国留学托管 The Great Wall of China is an immensely long man-made wall that was built to keep out invaders.The Great Wall spans nine provinces and its total length is 6,700 km (3,948 miles).The Great Wall extends from ShanHaiGuan (the 'Old Dragon Head'),a seaport along the coast of BoHai,in the east (near BeiDaiHe resort) to JiaYuGuan Pass in GanSu Province in the west.Like a giant dragon,the Great Wall of China winds its way across grasslands,deserts and mountains.