Two pencil sketches and few beautiful wallpapers of the Great Wall of China. The Great Wall of China remains a construction feat unequalled in it's over 25,00 years of existence. Its average height is about 30 feet and 15 feet in widths. It stretches over 4 thousand miles across a number of China's most forbidding terrain, from the Korean hills to the Gobi desert. Elements of the wall were in-built the seventh century B.C by the feudal states that wished protection from northern invaders. However its real history began with the primary Qin emperor, who unified China in 221 B.C. He connected the previous walls and extended them to over three thousand miles. The wall visible nowadays was given its form within the Ming dynasty, a project that took two hundred years to complete (1368-1666). The wall is created principally of rocks and packed earth, however the Ming builders gave it a facing of Kiln-fired brick. They additionally added watch towers and cannons for more protection.