Grotte di Castellana

The Grotte di Castellana are the most extensive show cave system in Italy, stretching more than three kilometres beneath the karst plateau of the Apulian interior, about 40 kilometres south-east of Bari. Discovered in 1938 by speleologist Franco Anelli, the complex opens into La Grave — a 60-metre-deep natural shaft open to the sky, its walls covered in ferns and moss — before descending through a sequence of progressively dramatic chambers. The cave system formed over millions of years as rainwater dissolved the limestone bedrock, creating passages, stalactite forests, and subterranean lakes. Two guided tour routes are available: a short route of approximately one kilometre (around 50 minutes) covering the most accessible sections including La Grave; and the full three-kilometre tour (around 100 minutes) that continues to the Grotta Bianca — the White Cave — where pure white selenite crystals and alabaster stalactites create a chamber widely considered the most beautiful natural cave in Italy. Temperature inside holds at a constant 15°C year-round, making the caves naturally cool in summer and mild in winter. Independent entry is not permitted; all visits are guided. The cave floor is paved and well lit throughout the accessible sections, though some passages require ducking. Booking in advance online is strongly advised from May through September, when tours fill weeks ahead. The visitor centre at Castellana Grotte includes a café, geological museum, and gift shop. Photography without flash is permitted throughout. The caves are 40 km from Bari by road and 45 km from Alberobello, making them a natural pairing in a southern Apulia day itinerary.