One of the largest and most monumental karst phenomena in Romania, Cetățile Ponorului (Fortress of Ponor) are not actually a built fortress, but a natural lime formation stretching in northern Bihor Mountains, Apuseni Mountains in Padis region, a well-known touristic area.
Also dubbed as the Everest of the Romanian speleology, the karst complex of Ponor was firstly mention by Nagy Sandor in 1886. Cetățile Ponorului were declared a natural reservation in 1952 and soon after that they became a natural monument.
Cetățile Ponorului basin has an area of 36 square kilometers (including Galbenei Gorge and The Flowers’ Glade) in the southwestern part and of Someș Gorges, Vărășoaia Glade and Căciulata Glade on the northern side of the river.
These fortresses consist of three large circles of stone (dolines), which are 300 meters deep and more than 1 km in diameter. The formation has 3 doline entrances and 4 balconies that stand on top of the Fortress. The name of the Fortess of Ponor comes from what it may be called the surface sector of this karst phenomenon.
The access way starts with a forest road that leads to the first circle (Doline 1) by passing a bump field which is parallel to Cetatilor Valley. The lateral Western wall (more than 150 meters high) presents a portal whose altitude is higher than 70 meters.
A scree mosaic leads to the second doline through an arcade. This second doline is a circular abyss that has an altitude of 200 meters.
The third doline can be reached by climbing the metal stairs that are located to the left of the portal.
Two of the balconies are situated above the third doline and the other two above the fourth doline.
Species of plants that can only be found in the Northern Europe or in the tundra also grow here. The landscape is amazing, because of the pine trees , but also due to unique phenomenon– in the valleys of the mountains, one may see coniferous forests and on the peaks of the mountains there are deciduous trees. This phenomenon is caused by the thermic inversion, which is triggered by the karst areas, and as a result, the temperature in the valleys is much lower.