Here guided tours take you 270m below ground and through seven chambers with such fanciful names as Sanctuary of the Fairy and Zeus’ Palace. All teem with illuminated stalagmites and stalactites shaped into drapery, organ pipes, domes, curtains, waves and other strange formations. The cave is home to more than 400 bats, who may greet you if you visit in the morning.
Tours run roughly every 45 minutes and take about 40 minutes. A 150m-long walkway makes the cave accessible to everyone.
There's a decent cafe to help pass the time if you need to wait for the next tour. From Monday to Friday two daily buses make the trip out from Rethymno (€6, one hour, 5.30am and 2pm).