Akiyoshidai, located in the midwestern part of Yamaguchi Prefecture, in a quasi-national park famous as one of Japan's largest karst plateaus. This kind of terrain is filled with white limestone rocks that rise above the grasslands as far as the eye can see. There are also many huge limestone caves scattered underground. Among them, Akiyoshido, which is designated as a special natural monument, is a huge limestone cave with a total length of over 10km, and a sightseeing course of about 1km. The temperature is constant at 17 degrees Celsius throughout the four seasons, and it is cool in summer and warm in winter, making it an ideal place for sightseeing. Inside the limestone cave, visitors are fascinated by the mysterious formations that have naturally formed over a long period of time.