Capri holds a treasure: it is the Blue Grotto, a jewel discovered long ago by the Roman emperors. Not by chance, they were far sighted and took advantage of the cave entrance - often hidden by the tides - to create their own private natural pool.
According to the historians of the times, Emperor Tiberius built a passage connecting his house to the cave, even if the tunnel - which probably later collapsed - was never found. The emperor used the cave as a “sea nymphaeum”. What is now left, close to the entrance of a tunnel, are the remains of a roman harbor.
For a long time the Blue Grotto fell into oblivion: local sailors and fishermen were scared, since -according to some popular tales- it was infested by ghosts and demons. Although shrouded in mystery, some fishermen kept in their memory the Blue Grotto and how to access it. During the the first half of 1800, one of them let two german artists inside the grotto, exploring it for the first time after ages: they were Ernst Fries and August Kopisch, a painter and a writer. They started narrating with awe and astonishment their extraordinary discovery. Since that day the shimmering cave became famous all over the world.
The light enters the cave both from outside and inside through an underwater breach, creating bluish color effects and turning into different colors depending on the time of day and weather conditions. This circumstance caused the natural monument to become a cherished destination: the most visited in the area, coming only after the excavations of Pompeii and the Royal Palace of Caserta.
To access the grotto visitors almost have to stretch out in the small boats which cross the entrance arch, that can become larger or smaller depending on the tides. Once inside, as eyes get accustomed to the lack of light, after a moment, when completely immersed in darkness, the miracle can be enjoyed: hit by the light, underwater rocks show silver reflections.
They originate from light refraction: the refractive indexes of air (the bubbles lying on the surface of the submerged objects) and water are different, hence light is refracted. The natural cave is about 60 meters long and 25 wide. On one side, the “gallery of the pillars” looks like being naturally supported by impressive stalactites.