The Great Wall of China

Building of the Wall began over 9,000 years ago and was initially hundreds of miles of separated fortifications built by various rulers of China's independent states. But around 220 B.C., Shi Huang Di became the first emperor of a united China and decided that the various walls needed to be fortified and joined together. He ordered thousands of watchtowers to be built 12 metres tall and 12 square metres at their base with 6-metre walls of granite joining them. This was obviously a massive undertaking and required thousands of workers. Over 300,000 workmen, criminals and political prisoners were dragged off to build the wall. Many died from malnutrition, fighting, or just plain exhaustion before even getting to the construction sites. . There wasn't always rock available, so they used earth and rubble that they pounded until it was hard. In other places the hills were so steep that oxen couldn't pull the carts of rock up to the building site, so the men themselves carried the rocks on their backs. In the desert, the wall was built using sand, pebbles and grass.
But why go to all the trouble? The obvious answer is protection: keeping enemies of the empire out, although, at the time construction first began, China didn't have any powerful enemies. Besides, the wall would require far too many people to man it. It seems the wall may have been much more effective at keeping the Chinese people in than at keeping enemies out. But Some say the wall was really built to satisfy the emperor's paranoia and his love of grandiose schemes and that his officials supported the excessive structure as it was also a great way to keep criminals busy.
Whatever the emperor's reason, he didn't live long enough to play it out. He died in 210 B.C. and thanks to a lot of squabbling and deceit, his dynasty, called the Qin dynasty, collapsed only four years later. The Han dynasty that followed used the Wall effectively to ward off enemies, but after that dynasty's collapse, enemy tribes gained power in the north, and held it for some 400 years. It was refortified, and in the 13th century A.D., the Mongol invader Genghis Khan took two years to break through it.In the 14th century, the Ming dynasty did some extensive renovations to the badly eroded wall, extended it to its 6,400 kms. and added cannons, and decorations. Today, The Wall is considered one of the great wonders of the world. UNESCO (United Nations Educational, Scientific and Cultural Organization) put it on the world heritage list in 1987 to ensure its preservation and its place in history.
When the Manchus took control of China in 1644, the wall ceased to have military significance. The empire now extended well north of the wall, and China's new enemies were to come from a different direction - across the sea. Today, although the wall no longer plays any role in China's defence system it has become a symbol of the nation and the ingenuity and will of the people.