Grotta Azzurra
The Blue Grotto (Grotta Azzurra) is a noted sea cave on the coast of the Italian island of Capri.
The grotto has a partially submerged opening into the sea, as do other grottoes into the island. Roman emperors with villas on Capri reportedly used the Blue Grotto as a private bath. In modern times, it has become a popular tourist attraction, with visitors touring it by boat.
Depending upon the tide and the size of the swells pounding the entrance to the grotto, the guides will have passengers lie down while they pull the boat and sightseers into the grotto with a chain permanently attached to the cave entrance.
Inside the grotto the sea seems to be lit from underwater. It is a magnificent fluorescent blue colour, hence its name. The underground passages leading to the grotto are partially sealed and supposedly once were connected to catacombs of Roman tombs.