The phreatic cavities characterize properly the coastal karst, though very influenced by the coastal evolution.
The floored group of rooms, galleries and also fractures and for the human impenetrable spaces constitute the habitat of interesting exclusive organisms of underground aquatic environments. They are an important part of the biodiversity, many of them endemic and with abundant adaptations to this habitat.
In some of the cavities with salt waters, it is to emphasize the presence of communities of filtering organism, which are fizzed on roofs walls, formations, stones and in some cases in the cave-bed sediments.
Other organisms of diverse kinds colonize only the nearest sectors to the sea, or are occasional visitors of caves with direct entry.
The caves catalogued as Sites of Community Interest in Manacor are: the Cova d´en Bessó, the Cova de Ca´n Bordills, the Cova dels Diners, the Cova del Dimoni, the Cova de sa Gleda, the Cova des Pirata and the Cova des Pont.
Coves del Drach is a group of natural caves extends over a distance of 1.700 m. Its stalagmites have got big dimensions and irregular shapes, while the stalactites are thin and plentiful. Nowadays the course is of 1km approximately, and for the visitors every day concerts as classical music take place on the famous Martel lake.
Discovered by Pere Caldentery these caves are famous for their peculiar arborescent formation and its marvellous subterranean lake, where extraordinary concerts take place. A visit to the caves will allow you to meet their inhabitants prehistoric crustaceans which have survived the passing of time.
The aquarium atoned in 1974. There are 115 fish tanks on two floors. In there, the Mediterranean submarine flora and fauna as well as fish from the Australian coral barriers and other, smaller ones, from Brazilian rivers, piranhas, etc. can be discovered.