It has been estimated that Istria has more than two thousand caves, dens and pits. Caves Baredine, Pazin, Mramornica, Romualdo's and Festinsko Kraljevstvo are set up for tourism, but there are many other underground caves and pits running through its karst landscape. It is possible to visit many of the pits and caves without special speleological knowledge and equipment, but there are many others that require more experience and special equipment to catch a glimpse of their underground halls, lakes, streams, abysses, whirlpools, cracks, and petrifactions. Besides the natural beauty of the cave formations, there is a heterogeneous world of flora and fauna in the caves and holes of Istria - fish, frogs, dormice, small crabs, bats, and others. The most interesting of these is the Proteus, an amphibian that is endemic only to these karst regions.
Among the best known caves in Croatia to speleologists are three Istrian caves: Cave near Raspor (Cicarija), Semicka Cicarija and Klanski gorge (Gotovz).
