Blue Grotto of Capri

ocean · caves · Italy · light science

Glowing blue water. Sunlight travels through an underwater opening, bounces off the sandy bottom far below, and comes back up through the seawater, making it glow an amazing electric blue.

Located in Capri. This incredible cave sits on the coast of Capri, a famous island in southern Italy surrounded by sparkling Mediterranean Sea.

Surprisingly deep. The cave stretches about 160 feet into the cliff and drops down approximately 490 feet deep with a sandy floor.

A natural light show. The blue glow you see is actually sunlight being reflected and scattered by the water and sand, which makes blue light stand out more than other colors.