Location:  Great Wall is located along the northern and northwestern frontier of China, running from Jinwangdao on the Gulf of Chihli (Bo Hai or Po Hai) on the east to the vicinity of Gaodai, Gansu Province on the west.

Description:

The Great Wall was built as a defense against invaders. Guards were posted along the wall so that they could sound the alarm if danger threatened. The two parallel walls, made of earth and stone, are both 30ft in height and was a width of 10ft.

 History:

This huge fortification was begun by the first emperor Shi Huang Ti of the Ch'in dynasty. Systematic work on the wall was begun about 221 BC, and it was finished about 204 BC. Shi Huang Ti is supposed to have had some 1900 km of the wall erected during his reign. During the period of the Ming dynasty (AD 1368-1644), the Great Wall was repaired and extended. The fortification finally reached a length of about 4000 km.