Although the facilities here are run-down, this two-million-year-old cave is one of the finest in Greece, covering 3300 sq metres and containing stalagmites and stalactites. It's well lit, and guided tours end with a quirky sound-and-light finale set to classical music.
The cave is best visited by car. Buses 125 and 308 from outside Athens’ Nomismatikopio metro station can take you as far as Peania, but it’s a further 4.5km to the cave.