Ojców National Park was established in 1956, and is the smallest national park in Poland. The park is located in the southern part of the Krakow-Czestochowa Upland. The park is home to karst forms (monadnocks, caves, karst valleys, gorges, etc.), which were formed as a result of the karstification process - water containing carbon dioxide dissolved limestone rocks. One such rock, which has a unique shape, has become a symbol of the park. This is the famous Mace of Hercules - a limestone rock formation with vertical walls 25 meters high. Also interesting is the Cracow Gate, which is a natural rock gate built of 15-meter-high blocks of Jurassic limestone. Other interesting karst forms found in ONP are caves. So far, about 400 caves have been discovered and described, but it is believed that there may be as many as 700 in the park. Noteworthy are the two longest caves - Jaskinia Łokietka (320 m long), and Jaskinia Ciemna (230 m), which is one of the most important archaeological sites in Poland. Ojcow's caves are home to 17 species of bats - it is this small mammal that appears on the park's logo. Within the park you can visit the ruins of the fortified castle in Ojców and the beautiful Castle in Pieskowa Skała, built on a limestone rock. One of the main tasks of the Pieskowa Skala Castle was to defend the trade road running from Kiev through Kraków to Silesia. It is worth mentioning that the Eagle's Nest Pedestrian Trail and the Jurassic Eagle's Nest Bicycle Trail run through ONP.