Una National Park, in the Bihac municipality, encompasses the valley of the Una River and is a hotspot for speleological research expeditions. Thanks to the area's position between the end of two large karst systems: Plješivica and Grmeč, the river abounds with shallow water sources and a significant number of underwater caves. So far, 10 large caves have been registered, only five of which have been partially examined. Divers who have explored Klokot Spring have managed to reach a depth of , though the bottom of the spring has yet to be touched. Another cave has been explored to the length of , and is said to be an ideal destination for cave divers in training.