225 million years ago the area of the Aggtelek Karst was covered with a warm sea. Sea animals with shells were abundant in it. Due to geological processes the deposited calcareous shells were formed to be the basic rock type of the karst.
About three million years ago caves of the karst began to evolve. All the caves of the Aggtelek and Slovak Karst were entitled to World Heritage Sites by the UNESCO World Heritage Committee in 1995. Currently more than 1200 caves are known in the karst. The underground world is nearly untouched with a lot of different rock and mineral formations.
The Aggtelek Karst is well-known of its caves, although, the kast formations on the surface are also very variable. Swallets, dolinas, and blind valleys can be found on the karst plateaus and slopes. Valleys and canyons have been continuously formed by streams. Bizarre rock formations and several types of limestones remind visitors for the richness of inanimate nature.