Grotta Verde, Sea cave in Capri, Italy

Grotta Verde is a sea cave on the southern side of Capri, in the Anacapri area, with two openings: a western threshold four metres below sea level and an eastern one at sea level, seven metres high. Its walls, widened by rockfalls, follow an irregular course through dolomite, the island's oldest sedimentary rock, formed 190 to 130 million years ago.

Known since the 16th century, the cave was first called grotta dei Turchi because corsairs such as Dragut and Barbarossa attacked Capri and likely hid their ships inside to raid passing vessels. It took its present name later. From the 19th century, when boat tours around the island became customary, it joined the Blue Grotto and the Faraglioni as an attraction.

The cave was long known as the Grotta dei Turchi, a name recalling the 16th-century raids on Capri by corsairs such as Dragut and Khayr al-Din Barbarossa, who destroyed the castle of the same name. Corsairs likely used the cavity to ambush passing boats. From the 19th century, when boat tours of the island became customary, the cave was promoted alongside the Blue Grotto and the Faraglioni.

The cave is reachable only by boat when sea conditions are calm, and you travel in a small vessel that enters the water passage to reach the opening. Visitors should be flexible with timing and wait for good weather, as rough seas can make access impossible.

The cave has two openings, called thresholds: the western one lies four metres below sea level, while the eastern one sits at sea level and is seven metres high. The green colour comes from light entering through the submerged threshold and varies with the hour and the weather.