The bone-shaped, beautiful Lake Ashi never freezes over, due to the constant volcanic heat beneath its surface.

The lake lies in the crater of a volcano that last erupted hundreds of thousands of years ago, and now boasts two - either tacky or great fun depending on your mood on the day - pirate ships that sail on the lake. Whatever your mood, the boats are a good way to explore the lake and to take in the spectacular views along its shores.