Blue Cave is located in a small bay called Balun, on the east side of Otok Bisevo and about 4.5 nm south-west of Komiža (Otok Vis) and is one of the natural wonders of Croatia. The cave is 35 m long, 17 m wide and 6 m height. During the day the water glows blue in several pools inside where the sun light penetrates by means of an submerged passage.