Danyang Jeokseong Fortress (단양 적성)

Danyang Jeokseong Fortress is a fortress made of stones gathered from Seongjaesan Mountain in Danyang. The fortress was built surrounding the mountain's southern slope and summit. <br><br> The fortress had a circumference of 923 meters, but most of it has been destroyed; the only remaining section is a 3-meter part of the inner wall in the northeast quarter. Three gates were found in the southwest, east, and southeast areas. Inside of the fortress is a stone stele.