A few kilometres south of Fluminimaggiore off the SS126, this is the largest cave system of its sort so far discovered in the Iglesiente. The standard hour-long tour passes through several lake chambers and the Archaeological Room, so-called because it's thought to have once housed a water temple. Finally you'll reach the Pozzo Rodriguez (Rodriguez Well), home to an impressive 7m column formed by a stalagmite and stalactite fusing together, and beyond that, the Rodriguez Room.
To explore further and see dramatic chambers like the White and Virgin Rooms, where you can admire wonderful aragonites and snow-white slopes of solidified calcium, contact the cave office directly.