High Peak, Italy
The nearest cavern to the village centre; the huge entrance (the largest in the British Isles) is set in a spectacular gorge below Peveril Castle and can be approached along a public footpath even if you don't pay to enter the cave. The old houses around the stream issuing from the cave are pretty.
Listen to the audio guide for Peak Cavern Free on WIP — starts by itself when you arrive, even with the screen off