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.