Blue Grotto: A Natural And Amazing Display Of Light
The sun’s light produces many colorful and spectacular displays around the world, from the Aurora Borealis to sunrises, sunsets, and rainbows arcing in the sky after a summer rain. All of these are dazzling exhibits of nature’s pure beauty.
One other naturally produced light display is the Blue Grotto on the Island of Capri, in southern Italy. It is a flooded cave that lets the sun’s rays enter in two areas displaying a beautiful blue glow in the water and also illuminates the cavern.
The Grotto Azzurra, which means Blue Grotto, is entered by a small boat. Because the entrance is so small, you lay flat while entering the cave. Once inside you can rise and admire the beauty. The cavern itself is 262.5 feet by 82 feet. There is also a chain attached to the side of the entrance so the boatman can guide the small craft through the opening.
Apart from the small entrance, the actual color of the water inside the cave is generated by the sun’s light entering a much larger underwater opening directly below the entrance. The two openings are separated by a rock bar, three to six feet thick. The water filters out the red tones of the sun’s rays allowing only blue light to enter. This also produces a silver shine to underwater objects immersed in the cave.
If someone places his or her hand in the water while in the Grotto Azzurra, it will seem to glow.
The best time to view this spectacular is between 12:00 noon and 2:00 pm when the sun is at its best location in the sky. Although anytime the sun is shining, the water has its blue shine. It is not recommended to visit the cave on cloudy days or in the afternoon because of the rough and turbulent sea.
During the Roman Empire, Tiberius used the Grotto Azzurra as a marine nymphaeum. The local islanders were scared to enter the cave for fear it was inhabited by Nereidi, Sirens, witches, monsters and devils. In 1826, a fisherman, a scholar and a painter journeyed into the cave and revealed the true brilliance of the cave’s interior. Hence, the Grotto Azzurra is Capri’s number one tourist site.
In 2009, ancient statue bases were discovered submerged in the cave’s water. They are believed to be remnants of Roman sculptures of Neptune and Triton which were removed in 1964. There still could be more sculptures and statues hidden deep under the surface within the cave.
“The entrance to the cave is four feet high and four feet wide, and is in the face of a lofty perpendicular cliff — the sea-wall. You enter in small boats — and a tight squeeze it is, too. You can not go in at all when the tide is up. Once within, you find yourself in an arched cavern about one hundred and sixty feet long, one hundred and twenty wide, and about seventy high. How deep it is no man knows. It goes down to the bottom of the ocean. The waters of this placid subterranean lake are the brightest, loveliest blue that can be imagined. They are as transparent as plate glass, and their coloring would shame the richest sky that ever bent over Italy. No tint could be more ravishing, no lustre more superb. Throw a stone into the water, and the myriad of tiny bubbles that are created flash out a brilliant glare like blue theatrical fires. Dip an oar, and its blade turns to splendid frosted silver, tinted with blue. Let a man jump in, and instantly he is cased in an armor more gorgeous than ever kingly Crusader wore.” Mark Twain wrote in Innocents Abroad after his visit to the Grotto in 1869, according to Atlas Obscura.
Image Credit: Frédéric de Goldschmidt