Great Wall of China
photo taken from nationalgeographic.com
The Great Wall of China is a stone fortification that was built, rebuilt, and maintained between the 5th century B.C. and the 16th century that was used to protect the northern barriers of the Chinese Empire from Xiongnu attacks during the rule of successive dynasties. The wall stretches for approximately 4,160 miles. It has been estimated that 2-3 million Chinese died as part of the long project to build the great wall. This is definitely one of the most fascinating man-made developments in human history.
If you would like to learn more about the Great Wall of China, you can check out Wikipedia’s article, The Great Wall of China.