Great Wall of China, China

One of the seven wonders of the world, the Great Wall of China is a man-made structure that was constructed over two thousand years ago and took about 100 years to complete. The vastness of this project brings to light the immense capabilities of man.

The constructions started in the 5th Century B.C. It is actually not a single wall, but rather many walls put together, and it stretches over 4,000 miles. It was constructed to protect the Chinese Empire from the Xiongnu people in the north. The wall was initially built of stone, grass, earth, and wood, but bricks were used once the production started. It is believed that about 2-3 million Chinese died during the construction project.