When they reach the plaza the bathhouse looks out on, they'll find the fountains there running, shooting water high into the air in intricate patterns.
The bathhouse itself is a tall, unevenly terraced building, some of those terraces filled with pools, others not. The edges of the pool-less ones are spaces for greenery - wild, overgrown dark flowers of undeterminable colour spill out of them over the side of the building, lending the air their sweet, heady scent.
The water in the lower pool terraces spills over the edge to fall in certain parts of the next one down, while the upper ones are serene and still. A light steam rises up off the pools, leaving what they can see of the covered parts of the building hazy and indistinct.
The entrance is on the ground, facing the plaza, but of course they can just land on one if the terraces.