Built for the protection of the people of china, the Great Wall of China is a series of walls built with stones in the northern borders of china. With a length of about 6,400 km, it is the longest man-made structure and one of the greatest wonders of the world. It is also the only man-made structure visible from the moon. In 1987, UNESCO listed it as a World Heritage Site.

Several walls were built to prevent china from nomadic people such as Xiongnu in the north and were referred to as Great Wall. The most famous of them is the Great Wall built by the first emperor of china ‘Qin Shi Huang’, between 220-206 BC.
Chinese are considered masters of art. They had mastered the art of wall-building as early as 8th century BC. During the Warring States Period, the Qi, Yan and Zhao dynasty emperors decided to build walls for protection against small attacks of spears and swords. The walls were built by stamping earth’s gravel in board frames.
Soon Qin Shi Huang conquered china and established Qin dynasty. In order to prevent resurgence of feudal lords, he ordered for the destruction of the walls that divided his empire from other state borders. Soon his empire started getting invaded by the nomadic peoples such as Xiongnu in the north. To protect his empire, he ordered the building of a wall, the Great Wall of China. Constructing of this monstrous wall was not easy; they needed huge amount of materials. As the transportation of these materials again was very difficult, they used local materials such as stone and mud. Stones were brought from the mountains.
The wall was not so strong; it could not stand for several years, as china was further conquered by other emperors. Several sections of the wall got collapsed. Later, the Han, Jin, Sui, and Northern dynasties rebuilt the collapsed walls.