Grotta dello Smeraldo – Emerald Grotto

Partly submerged cave in Amalfi Coast, Italy. Sunlight enters the cave indirectly – through the seawater and most of the visible spectrum is absorbed. Thus the water in one corner of the cave shines in a beautiful emerald green-blue color.

Blue Grotto in Capri

Inundated cave with a beautiful effect of sunlight in water.