Construction on The Great Wall of China was started in approximately 220 B.C. as a means to prevent barbarian nomads from invading the Chinese Empire. As it never effectively prevented invasions, the Great Wall came to serve more as a psychological wall between China and the outside world.
The Great Wall is an assembly of walls and fortifications built over the course of hundreds of years. Most of the Great Wall still in existence was constructed during the Ming Dynasty in the 14th century. While the Chinese were locked in an ongoing conflict with Mongolian tribes, they turned their attention to wall building on the country's northern border. The wall was a key component in a largely defensive stance adopted after a period of expansion. While early sections of the wall were constructed of rammed earth, Ming construction incorporated the use of bricks and stone. During this period, thousands of watchtowers were constructed on the wall.
The Great Wall is widely recognized as one of the most-incredible architectural accomplishments in history, though as many as 400,000 workers died early in its construction. While portions of the wall are in poor condition, it continues to serve as a powerful symbol of Chinese strength.