The fortress(wall), which follows the ridges of Bugaksan, Naksan, Namsan and Inwangsan, the four main mountains surrounding the center of Seoul, has been constantly managed since its initial construction in 1396. The fortress measures between 5 and 8m high and is 18.6km long and it bears witness to the role played by a city wall in the life of a capital city of Joseon Dynasty, still sustained in modern day Seoul.