Grotta Azzurra is a sea cave located on the island of Capri in southern Italy. Visitors can enter the cave by small rowboat, lie back to pass through its narrow entrance, and then observe the illuminated blue waters while taking photographs and experiencing the quiet interior. The grotto is known for its vivid blue colour caused by sunlight passing through an underwater opening, and it was used in Roman times as a personal swimming hole, with remains of sculptures and structures still linked to its history today.