Three different limestone caves are located a few kilometers outside of Gujo's town center. Otaki Cave (大滝鍾乳洞, Ōtaki Shōnyūdō) is the most popular among them, and during the summer holidays, the site bustles with souvenirs shops and restaurants serving nagashi somen noodles.
The Otaki Cave was named for its interior waterfall that stretches 30 meters high. It is the tallest underground waterfall in Japan. A small cable car takes passengers up to the cave entrance where they are left to complete the walking course at their own pace. The course through the cave takes about 30 minutes and is well marked, though the steep, narrow staircases may be difficult to navigate for some.