If you planning to visit Beijing, China anytime soon, then a must-see is definitely the Great Wall of China. Despite popular belief, the Great Wall cannot be seen from space. It measures 5,500 miles (8,850 km) and is made up of 3,889 miles (6,259 km) sections of actual wall, 223 miles (359 km) of trenches and 1,387 miles (2,232 km) of natural defensive barriers such as hills and rivers.