

There’s one made of stone and a natural brook runs through the floor.
In the winter there are several saunas built from snow / ice. The snow sauna is said to be an especially pleasing experience.
There are sauna rafts that have engines, so you can cruise around the waters.
There are car trailer saunas that you can rent and drive to any open beach you wish. Or your own backyard.
And probably a whole lot crazier ones that I can’t remember right now.
I think there’s also one on a ski lift gondola in Lapland…