The Speleovivarium was designed to replicate a grotto; it’s not lit and there is high humidity and temperature stability. There is an extraordinary range of cave fauna in this unusual place where at one time would have only been seen by speleological experts. There are special aquariums and tanks with very rare animals like troglodytes, amphibians, and fish that have come from hypogeum environments outside Europe. In a separate section dedicated to an amphibian, which is of enormous scientific value and at risk of extinction, is the olm. This lives in the deep waters of the Trieste Carso.