The Apostle Islands are low forested islands. Many have campsites and trail systems, although it's hard to understand why anyone would walk around an island rather than paddle. There are 21 major islands, of which most are in the Gaylord Nelson Wilderness Area.
It's hard to get good photos from a sea kayak because I'm always afraid I'll go over and destroy $2K worth of camera gear. It's doubly hard in a sea cave because you can either expose the dark inside of the cave or the bright outside, but not both, as seen in some of the previous photos.
However, now and then, even a beginner has the good luck to get a photo showing what it's like inside the caves. This photo is a combination of both natural light (to the left) and a flash (to the right).