Danyang Ondaldonggul Cave | Danyang-gun, Chungcheongbuk-do

The Ondaldonggul Cave is located underground at the foot of the Seongsan Mountain. This cave makes a perfect all-year-round attraction, featuring a stairway structure and an abundance of beautiful stalagmites and stalactites that you will find inside. Situated on top of the mountain peak to the left of the cave is the Ondalsanseong Fortress. The annual Ondal Culture Festival is held here every October between the cave and the fortress to celebrate the memories of the legendary love story between General Ondal and Princess Pyeonggang.