The most spectacular cave system in southern Italy and among the finest in the Mediterranean. The complex runs nearly four kilometres underground, reaching a depth of 70 metres, and takes two main forms as a tour: a shorter circuit of about one kilometre (roughly 50 minutes) covering the main chambers, or the full tour of the entire system (roughly two hours) that ends in the luminous Caverna Bianca — a chamber of white calcite so pale it seems to glow.
The full tour is the one to take. The Caverna Bianca alone justifies the extra time: the white aragonite formations here are among the most photographed geological features in Italy. Go on a weekday if you can — summer weekends bring long queues. Tours run daily year-round; in high season there are options in English, French, and German as well as Italian. Sturdy shoes are essential; the paths are uneven and damp in places.