Don't forget to bring your camera to capture the flowing cascades of Senryugataki Park. If it's raging, you may be able to feel the mist on your skin.
This cascade of water is located in Sasebo, a place that has lots going for it! Matsuura City Office, and Shikamachi Onsen are other good sightseeing opportunities nearby when you're all done at Senryugataki Park.