Badaling is located in Yanqing County, about 60 km (37 miles) from downtown Beijing. It was initially built in 1505 of the Ming Dynasty (1368 - 1644), and was reconstructed many times. In 1582, it was built into a long great wall armed with gates, fortresses, and the signal fire security system. The wall was built on the mountains, so it is very hard to climb it. Therefore, Chairman Mao said 'he who does not reach the Great Wall is not a true man'.