The Postojna Cave is deemed the cradle of speleobiology, a branch of biology which studies the underground world. According to estimations by researchers, the Postojna Cave system hosts around 130 different species of animals. The Vivarium Proteus can present the visitors the basic discoveries, the history of Karst exploration and speleobiology, specifics of the underground ecosystem, and present the diversity of members of cave fauna. The visitors will view a multimedia presentation about Karst and life underground, and in vivaria in the Signature Tunnel, they can see live representatives of cave animals from the Postojna Cave, where special attention is given to the most famous of them all, the human fish (Proteus anguinus). In this part of the cave, there is also a speleobiological laboratory for the needs of scientific research. We recommend this visit to all those who wish to find out more about underground life.