Even though this place is called Sunyaragi Cave, it isn't really a cave. This is a man made building but it has a very unique construction. It was built in 1703 by one of the sultans of Cirebon as a water palace to relax with his harem. The locals say it is built from coral but I've yet to find out if that's true. In the 1800's the place was renovated by a Chinese architect and they say he was killed after so as not to reveal the secrets of the palace. Anyway, there are many stories surrounding this unusual building which I will translate and research some more. If your in Cirebon it's definitely worth taking an hour or so to look around this maze of man made madness.
This is located on the ring-road (by-pass). Easily reached by pedicab from the town centre. By car head North on the by-pass and you will see the building on you left before a set of traffic lights. Turn left at the lights and the car park is on the left as soon as you turn.
Google map link;