The Great Wall of China
They don’t call it great for nothing! The Great wall is the only man-made structure that can be seen from the moon. The ancient Chinese built the wall in 221 B.C. to ward off Mongol raiders. When added together, the wall spans 3,750 miles. Over a million workers including slaves, prisoners, peasants, and soldiers built the 10,000 battlements and watchtowers. The Great Wall is like the ancient Chinese described it: a slithering dragon resting on the backs of the mountains.
The main site is located about 50 miles northwest of Beijing, China. The best time to visit the wall is in the late afternoon, as then all of the tour buses have left and there are much fewer people. Even though only a third of the original wall is still standing today, the effect is no less magnificent. This is a showcase of superb engineering and what monolithic structures humans can create.