Rupnica, a unique Geological Monument of Nature is a special geological feature in the Papuk Nature Park and also the first proclaimed geological monument of nature in Croatia. It is a very rare morphological feature of volcanic rock and therefore was proclaimed as a protected part of the nature in 1948. Square and hexagonal prismatic pillars were created through columnar jointing of albite rhyolites. This morphological distinctiveness is the consequence of opening of the system of crevices when lava is cooling on its way out of the Earth. Rupnica is a part of the petrologically heterogeneous volcanic mass, inside which there are various kinds of basalt, andesite and tuffs. Rocks of Rupnica, according to the opinion of one group of geologists, were created 70 million years ago (Cretaceous). Another group of geologists supports the idea that volcanic body is much younger, created through evolution of the Pannonian basin (Miocene).
On the very locality a short educational path was made with educational tables. Visitors can find out more about Rupnica and volcanism, as well as volcanoes this way.