Yogyakarta, Indonesia
This is a partly ruined complex built as a pleasure garden by the first Sultan in 1765. One of the bathing pools was dedicated to the sultan's harem, and he had a tower overlooking the area so he could take his pick. Towards the back of the complex is the original entrance to the pools, which used t
o be a small dock connected to a long-since-vanished river; a bit of snooping beyond this entrance will get you to a back street, where one can freely visit a fascinating network of tunnels and rooms, including an Escher-like series of interlacing staircases over what looks like a disused well.
Listen to the audio guide for Water castle Tamansari Free on WIP — starts by itself when you arrive, even with the screen off