The Great Wall of China,China

The Great Wall of China (220 B.C and 1368 - 1644 A.D.) China

There is little that can be said about the Great Wall of China that has not been stated over and over again throughout the wall's 2000 year history. Construction of the Great Wall started in 221 BC to defend the Middle Kingdom from Mongol soldiers. But many of the sections were already in place, built by a series of independent kingdoms stretched across the land, from Shanhaiguan on the east coast to Jiayuguan in the Gobi Desert – Emperor Qin Shihuang merely oversaw the joining of these walls.

The first chapter in the history of the Great Wall of China ended in 207 BC, when the last of the over 6 billion cubic feet of compacted earth was set into place. The Great Wall was only moderately effective in carrying out its purpose, even after it was faced with bricks and stones. It's real value came in the way it eased transportation throughout the land – acting as a kind of elevated thruway, equipment, goods and passengers could more easily traverse the arduous mountainous wilderness that enveloped the Great Wall.

The Great Wall of China was built to link existing fortifications into a united defense system and better keep invading Mongol tribes out of China. It is the largest man-made monument ever to have been built and it is disputed that it is the only one visible from space. Many thousands of people must have given their lives to build this colossal construction.