One of the largest man-made structures in the world, one that can even be seen from space, is the Great Wall of China, often called the Eighth Wonder of the world.
This engineering marvel is about 20 feet tall and 13 feet wide and winds for approximately 1,500 miles across valleys, mountains, and rivers -- from the Pacific Ocean almost half-way across modern China.
The Great Wall is a stone and earth structure built about 228-210 BC under the direction of the Chinese emperor Shih Huang Pi to keep out nomadic raiders living in what is now Mongolia. He joined smaller sections of wall that had been constructed earlier into one long fortification with towers at intervals.
