I just went to one in Milan, Italy and oh my God it was amazing.
It's the best one I've ever been at.
There was an inside pool with jacuzzi sprays.
There was an Outside pool with jacuzzi sprays.
There was a sauna outside that was built like a train carriage.
Inside, they had a lavender sauna room, so you could breathe in lavender scent.
They also had, (the first one I've seen), a cinema special effects pool.
You sit in the pool and a short film comes on. Rain starts happening in the film, and then hot rain actually starts coming down on you in the pool.
I was impressed!