Once in the grotto, it's safe to sit up again. Visitors are rewarded with the spectacular sight of the iridescent blue water, caused by refraction of sunlight in the cave. Rowers often sing, adding to the enjoyment of the trip. The grotto is small so only a few boats at a time are inside and each group stays only a short time. With a flash, it's possible to get some pictures. Unfortunately, my water shots didn't turn out very well.
The Blue Grotto has been known and used since prehistoric times. Stone artifacts were found inside the cave and it was a favorite pool of the Romans during the time Emperor Tiberius had his villas on the island.