Discovered in the 16C by fishermen, a 600m circuit of the cave has been open to visitors since 1954. Whatever the season, the temperature remains between 18 and 20°C. The water that penetrates the cavity forms the Lago Lamarmora, which at 100m long is one of the largest saltwater lakes in Europe. Light infiltrates at a single point in the cave; and there cave flora turn the walls green. After 153 steps, you reach the different chambers of the cave, named after the weird and wonderful shapes of their concretions (Christmas tree, basilica dome, organ).