The Shanhai Pass lies 15 kilometers to the northeast of Qinhuangdao, Hebei Province.

The city walls of the Shanhai Pass reach Yanshan Mountains in the north and extend to the Bohai Sea in the south. The Shanhai (mountain and sea) Pass was named after its location between the mountains and sea. It holds a very strategically important location, and is a vital passage between the northeast and the north of China. Moreover, it is against the mountains and faces the sea and thus enjoys a reputation as the No.1 pass of the Great Wall and the key to the defense of two ancient capitals -- Beijing in the east and Chang'an (today's Xi'an) in the west. The traitorous general of the Ming Dynasty, Wu Sangui once stationed large numbers of troops here and finally stroke and captured Beijing, together with troops of the Qing, put down the peasant revolt led by Li Zicheng.

The Shanhai Pass was built in the 14th year (1381) of the Hongwu reign in the Ming Dynasty (1368-1644). The famous general of that time, Xu Da, who followed and assisted Zhu Yuanzhang to establish the Ming Dynasty, led his troops to build city walls against the threat of Nüzhen in northeast China. The city walls look square, 14 meters high and 7 meters thick, with a perimeter of about 4 kilometers. It is tamped inside with soils and laid outside with blue bricks. There are four gates: Weiyuan Gate in the north, Wangyang Gate in the south, Ying'en Gate in the west and Zhendong Gate in the east, on which each is built a city tower. Now only the eastern gate is well preserved.

The huge pass is a quadrate city platform. The areas to the east of it is called outside the Great Wall, while to the west is inside. It is connected with the Great Wall on its north and south sides. In the middle of the platform is an arched gate built of bricks, on which is a two-storeyed double-eaved city tower, 13 meters high, 20 meters wide and 11meters deep, with nine bridges and covered by tiles. The double eaves are decorated with colored paintings. There is no door in the west and altogether 68 loopholes on other three doors. In front of the upper part of the lintel is hung a huge plaque that reads: "The First Pass under the Heaven with each word of 1.6 meters high, which was written by Xiao Xian, a successful candidate in the highest imperial examinations of the Ming Dynasty in the 8th year (1472) of the Chenghua reign. Ascending on the city walls, looking into Bohai in the south, you can see a vast expanse of misty and rolling waters, while looking over the lofty and majestic Great Wall, you will naturally have some heroic spirit.

The city walls are surrounded by accessorial military facilities such as semicircular protective walls, eastern additional walls and the Muying Tower, the Linlü Tower, the Weiyuan Hall and so on, which form the outside protection barrier of the city walls. The Weiyuan City on the Huanxiling, 1 kilometer to the east of the Shanhai Pass, together with the beacon towers scattered around the city walls form an impregnable defense system. The Shanhai Pass was a town of military importance in ancient Chinese history.