St Michael's Cave is a karst cave dug into the limestone by the erosion of water, which still has concretions in development. You can get to the terrace in front of the cave via a steep staircase carved into the mountainside near the ancient houses of the monks of the hermitage of San Michele. The history of the cave and the cult of St. Michael are intertwined. Over thousands of years the water has shaped various secondary arms of the main cavity, creating concretions of various types and columnar formations of stalactites and stalagmites now united. The cave is inhabited by bats hanging from the ceiling.