Mamula is located in the Herceg Novi part of the bay, between the Lustica and Prevlaka peninsulas, 6.3 km away from Herceg Novi. At the time when this part of the coast was under the rule of the Venetian Republic, the island was also known as Rondina. It is circular in shape, 200 metres in diameter. About 80% of the island's surface is occupied by the fortress, which was built in 1853 by the Austro-Hungarian general Lazar Mamula (1795-1878). The fortress, together with the fortifications of Arza on Luštica and the Fort of Prevlaka on Cape Oštro (Prevlaka), had an important strategic importance in the defence of Boka. In fact, during both world wars, the fortress served as a notorious prison known for its cruelty (Kampo Mamula). During the Second World War, the Italians set up a concentration camp there, in which a total of 2,300 people were imprisoned.

Blue Cave is one of the largest natural cereations in a series of caves on this peninsula, and was formed at the foot of a 30-meter-high cliff, as a result of thousands of years of sea waves hitting the porous rocks of Lustica. The cave has two entrances, smaller, on the south side and larger, 3 metres high and 15 metres wide, located on the southwest side. Boats and smaller boats can enter the cave through a larger entrance, which allows tourists to attend indescribable games of light and water in the interior. This natural hall, with a vault at 9 metres above sea level, is a unique stage of natural wonders, which will leave everyone who visits the Blue Cave breathless. When the days are clear and sunny, through the entrances of the cave, sunlight enters its interior, and there it refracts on the surface of the water in indescribable shades of blue making the water and cave walls the colour after which the cave is named.