Spa

You are greeted by a nice lady behind a counter, handing out towels as needed, and swimsuits if asked (think: Japanese onsen/sentou aesthetic)
To the left is a door with blue curtains for men, to the right another with red curtains for women.

The total floor area of the complex is undefined. Every time it is measured it has either grown or shrunk from the previous measurements. There are theories that the inside area of the floor is simultaneously smaller and larger on the inside than the outside, possibly changing its size according to how many people are expected to visit during each day. When the elves were asked if the now fourth bath/pool could be added and if there were room for it, they looked at the questioner weirdly and asked what he was talking about, clearly there’s already an empty space right behind the delegation that could fit the planned bath/pool in it without decreasing the surface area of the old ones.

Entry is free of charge, the floor is open all day, every day. The elves have the final say on who they allow into the saunas.”