The Great Wall of China

Qin Shi Huangdi was the first 'emperor' to unify all the warring rivals into one state called China- the name derived from Qin.

He ruled between 221 and 206 BC and began the project build the Great Wall. During the Ming dynasty (1368-1644) the Great Wall was repaired, rebuilt and completed.

The wall stretches for 6,350 Km and its purpose was to protect China from the Mongol invaders in the north.