Haemieupseong Fortress (해미읍성), built during the Joseon period, has been preserved almost fully intact. It is one of Korea’s most renowned cultural heritages.This fortress is a historic site in which a supreme commander of the army in Chungcheong-do stayed, and from which the great Admiral Yi Sun-shin worked. Furthermore, as Korea’s largest sacred ground, the site at which nearly 1,000 Roman Catholics were martyred, it was grounds for the Donghak Peasant Revolution and the Catholic Persecution during more modern times. However, a variety of fun and exciting events such as a Barracks Experience Festival and the National Ssireum Championship are held here as well.