The valley was formed mainly of limestone from the Upper Jurassic and Cretaceous periods, 150 million years ago. It is a karst ravine with perpendicular rocky slopes and a flat bottom. Increased lateral erosion led to the formation of rock terraces, i.e. flattening, which create picturesque gateways, rock spires and other rock formations (e.g. the Kraków Gate, the Deotyma Needle). On the preserved terraced levels rise the ruins of the Ojców Castle and the Pieskowa Skała Castle. It is also here that the famous Hercules Mace can be found. There are also numerous caves (including the Ciemna Cave). The Prądnik Valley can be explored on foot or by bike. While in the area, it is worth visiting the Ojców Trout Farm and the Chapel on the Water. Admission to the Ojców National Park is free.