GREAT WALL OF CHINA
The Great Wall of China snakes over deserts, hills, and plains for several thousand miles. At its closest point it is less than 40 miles (65 km) from Beijing. Created after the unification of China under Qin Shi Huangdi (221–210 BC), it ultimately proved ineffective; it was breached in the 13th century by the Mongols and again, in the 17th century, by the Manchus. There are four main sites accessible from Beijing: Badaling, Mutianyu, Huanghua Cheng, and Simatai.