Formed over the course of 175 million years, Ryugado Cave (also known as “Ryuga Cave”) is one of Japan’s best-known limestone caves and has been designated a natural monument and historical site. Of the cave’s 4km length about one kilometer is open to the public. Serious spelunkers will enjoy the “Adventure Course,” which has low-ceilinged sections that require you to go on hands and knees, all the while relying on your headlight to see.

At the adjacent Ryugado Cave Museum you’ll find displays and artifacts, such as pottery, telling the story of the prehistoric Yayoi Period communities who dwelt in caves in the area from approximately 300 BCE to 300 CE.