Simatai Great Wall was originally built in 1368 of the Ming Dynasty (1368 - 1644), and was reconstructed by the famous Ming-Dynasty hero Qi Jiguang when he was the local official. Situated in the Gubeikou Town of Miyun County, 120 km (74.5 miles) from downtown Beijing, Simatai totals 5.7 km (3.5 miles) long from the eastern end Wangjing Tower to the western end Houchuankou. The wall as well as 35 towers was built on the ridge of a steep mountain, so Simatai is famous for its steepness and roughness.