Great Wall of China interesting facts you may not know

The Great Wall of China is a chain of fortifications constructed along the historical northern boundaries of ancient Chinese kingdoms. It's the world's tallest building. It measures about 21,196 kilometers in length, 9.1 meters in width (30 feet), and 15 meters in height. The wall was constructed by over 6 distinct Chinese dynasties over the span of hundreds of years and is over 2,300 years old.

The wall was constructed to keep northern invaders, like as the Mongols, at bay. Smaller walls had been erected throughout time, but Qin Shi Huang, China's first Emperor, felt that a single massive wall would be sufficient to defend his northern frontiers. Ming Dynasty constructed the most famous portions of the wall. The Great Wall of China was only broken once by Genghis Khan, the founder of the Mongol Empire.