When was the Great Wall of China built?
Construction of the Great Wall of China was begun during the third century B.C. by Emperor Shih Huang-ti (c. 259–210 B.C.) of the Ch’in dynasty (family of rulers). The immense structure was built as a protective barricade against invasion and was expanded over many centuries. The wall now stretches 1,500 miles, ranging in heights between 20 and 50 feet (6.1 and 15 meters), and is 15 to 25 feet (4.6 to 7.6 meters) thick. Guard stations and watchtowers are placed at regular intervals, but successive invasions of China from the north have proved the wall to be fairly ineffectual. Since 1949 a section of the wall in North Peking has been reconstructed and opened to visitors.
The Chinese were already familiar with the techniques of wall-building by the time of the Spring and Autumn Period, which began around the 8th century BC. During the Warring States Period from the 5th century BC to 221 BC, the states of Qi, Yan and Zhao all constructed extensive fortifications to defend their own borders. Built to withstand the attack of small arms such as swords and spears, these walls were made mostly by stamping earth and gravel between board frames. Qin Shi Huang conquered all opposing states and unified China in 221 BC, establishing the Qin Dynasty. Intending to impose centralized rule and prevent the resurgence of feudal lords, he ordered the destruction of the wall sections that divided his empire along the former state borders. To protect the empire against intrusions by the Xiongnu people from the north, he ordered the building of a new wall to connect the remaining fortifications along the empire’s new northern frontier. Transporting the large quantity of mat
