The city wall of Seoul was built in 1396 around the city during the Joseon Dynasty (1392-1897), and extends for a distance of 18.6 km along the mountain ranges of Bugaksan, Mt. Naksan, Mt. Namsan, and Mt. Inwangsan, and its height ranges from 7 to 8 meters. There were originally eight gates built between 1396-1398 AD, but only six of them still stand today. The northern, southern, eastern and western gates of the wall are known as the "Four Great Gates", while the northwestern, northeastern, southwestern, and southwestern gates are known as the "Four Great Gates." The four sub-gates.