I want to know about walls and fortresses
- Walls and fortresses are defensive structures built to protect towns or villages from enemy invasions. They have long been built ever since the system of rulers and subjects was formed in our history. Suwon Hwaseong Fortress was the last built fortress in Korea, under the reign of King Jeongjo in the late 18th century. Walls and fortresses are divided into four types by usage: Doseong (city wall), Sanseong (mountain fortress), Eupseong (town wall) and Jinseong (garrison fortress). They are categorized into four types based on construction materials: clay, stone, wood and brick.