Outdoors: Grotta dello Smeraldo

The Grotta dello Smeraldo (Italian for "Emerald Grotto") is a cave, partly inundated by the sea and located in Conca dei Marini, Italy, on the Amalfi Coast.

It is one of several caves worldwide, that are flooded with a brilliant blue or emerald light. The quality and nature of the color in each cave is determined by the unique lighting conditions in that particular cave. The grotto, which is located at the Amalfi Coast, is partly filled with sea water. The surface area of the water measures roughly 45 x 32 metres, with a cavern roof about 24 metres above water level. Formation of cave was caused by bradyseism - tectonic upheaval of cliffs, where cliffs fractured and cave was formed along the fissures. Now the cave has descended and sea water had entered it, partly flooding the stalagmites in it.

Unlike the Blue Grotto located a few kilometres to the west on Capri, the Grotta dello Smeraldo has no natural outlet above the waterline. The only opening to the outside world is just below the water level. Refracted sunlight entering the cavern through the opening gives the water its characteristic emerald glow during daylight hours.