Lake Akan is a caldera within the Akan National park. It was formed over 6,000 years ago from volcanic activity and is home to a rare form of algae called marimo (moss ball). The Marimo Exhibition and Observation Center is located on Churui Island in Lake Akan. The Marimo Exhibition and Observation center has displays of marimo in aquariums and provides explanations on the ecological significance of marimo. Churui means “rough, torrential waves,” in the Ainu language and is the only island in the lake that visitors can go ashore on. One way to reach the island is by a sightseeing boat which departs from Akankohan and cruises the lake for 1 hour. Akankohan is a lakeside hot spring resort and is the only town around the lake. On the eastern end of the town, there are walking trails that go through the forest, along the lakeside, and to boiling mud pools. It is about 500 meters north of the Akan Lakeside Eco-Museum Center where there is bubbling mud which is a result of the volcanic activity. This area is called “bokke,” which means “boil” in the Ainu language.