The monument was established at the site of a former quarry. This is a unique site in Croatia, where it is beautifully expressed stepped secretion of volcanic rocks. The columns are mostly upright than those in the central part of the outcrop which are bent. Who first saw the beautifully arranged pillars, remains amazed and surprised by the knowledge that it was the work of nature, or the volcano, we know only as sources of terrible destruction. Rupnica declared 14.10.1948. first protected geological natural monument in Croatia.