What makes the Great Wall of China so extraordinary - Megan Campisi and Pen-Pen Chen

View full lesson: http://ed.ted.com/lessons/what-makes-the-great-wall-of-china-so-extraordinary-megan-campisi-and-pen-pen-chen The Great Wall of China is a 13000-mile dragon of earth and...

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A 13,000 mile dragon of earth and stonewinds its way through the countryside of Chinawith a history almost as long and serpentine as the structure.The Great Wall began as multiple walls of rammed earthbuilt by individual feudal states during the Chunqiu periodto protect against nomadic raiders north of China and each other.When Emperor Qin Shi Huang unified the states in 221 BCE,the Tibetan Plateau and Pacific Ocean became natural barriers,but the mountains in the north remained vulnerableto Mongol, Turkish, and Xiongnu invasions.To defend against them,the Emperor expanded the small walls built by his predecessors,connecting some and fortifying others.As the structures grew from Lintao in the westto Liaodong in the east,they collectively became known as The Long Wall.To ac...