The Piatra Altarului (Altar Stone) Cave
Together with the famous Movile Cave, the Altar Stone Cave is considered a symbol for the karst phenomena of Romania, and is one of the most important in the world.

Extraordinary formations cover almost the entire cave. Varied and abundant calcite crystals, impressive large columns, or the discs considered a world's rarity give to this cave a fairytale appearance.

The Rece (Cold) Cave
Belonging to the same karst system with the previous one, the cave shelters archaeological vestiges, consisting of a ritualistic arrangement, in accordance with the cardinal points of four Ursus spelaeus skulls, probably suggesting a hunting ritual.

The Valea Rea (Bad Valley) Cave
Romania's greatest underground mineralogical "museum". Over 35 different minerals described as components of some speleological formations place this cave among the World's top 10 caves. It is also the most complex cave system in Romania (developed on about 20 km) including mineralized hydrothermal palaeo-karst (including native gold veins), relict hydrothermal but also cold water endokarst. The cave has the greatest vertical underground waterfall of Romania (the Ventilator Fall): 82 m high, 10 m diameter. It is the largest Romanian cave entirely developed in dolomites.

The V5 Pothole
The deepest Romanian cavity, reaching for now -642 m (the exploration is not finished), and more than 10 km in development. It has the largest underground hall in Romania (the Paul Matoş hall) of 1,200,000 m³ and a length of 415 m. Clusters of acicular aragonite crystals, some of them reaching more than 25 cm in length are found in some areas of the cave.

The Micula Cave
The Micula Cave is an especially beautiful cavity, rich in spelaeothemes of many varieties. Large spaces alternate with narrow and tall galleries, running waters and waterfalls, stalactites and stalagmites, columns, cave pearls and floating calcite which give a special charm to the cave. Of great value are also the palaeontological vestiges found here, including a cave bear (Ursus spelaeus) skeleton in anatomical connexion, but missing the skull.

The Zgurăşti Cave
Contains the largest permanent underground lake of Romania (65 m long, 20 m wide, 10 m deep – values for the mean water level). By its many lakes, it also represents the largest permanent underground water storage system in Romania (in the Mare, Ascuns, Velenţa, Lung and Styx lakes, comprising a total water volume of over 20,000 m³).

The Hodobana Cave
It is the most labyrinthine Romanian cave, one of the most labyrinthine in the world. It has 22,142 m of explored and charted galleries, on an extension of only 820 m (branch factor 27,00).

The Tăuz Karst Spring
Siphon no. 2 is the deepest explored underwater passage in Romania with a depth of -87 m.

The Coiba Mare Cave
Has the widest cave entrance in Romania (54 x 45 m = 2,430 m2), and also is considered the most outstanding sinkhole in our country.

The Fortress of Ponor Cave
Has the highest cave entrance in Romania, of 76 m.

The Scărişoara ice cave
Shelters the largest underground mass of permanent ice in Romania with a volume of about 75,000 m³.

The Living Fire ice cave
Is the third largest underground mass of permanent ice in Romania, with an estimated volume of 25,000 m³. Around noon, when the sun rays reach the block of ice through the upper entrance (which is a pothole), a spectacular optical phenomena is created, which inspired the name of the cave: Living Fire.

The Onceasa Cave
Is one of the most important palaeotological sites in Europe, especially because of the mass of fossil remains of Ursus spelaeus, but also other extinct species. Many nature museums in Europe hold fossil samples extracted from this site.

The Vârtop Cave (near Casa de Piatră hamlet)
3 footprints belonging to a group of Neanderthals were found in this cave (one of them is preserved at the „Emil Racoviţă” Speleological Institute in Cluj-Napoca, the other two were stolen soon after the discovery).

The Poieniţa - Humpleu Karst System
This cave system is the first in the Bihor Mountains regarding the development, having the biggest underground halls in Romania. The system, having two main exits, represents also the deepest underground hydrological crossing of our country (with a level difference of  402 m). The geode found close to the Humpleu entrance contains huge calcite crystals.

The Ponor Glade
Is the only karst plain in Romania.

The Sighiştel Valley
By its nearly 200 caves on a surface of only 10² km, the valley has the highest density of natural cavities in Romania.

The Bears Cave (from Chişcău)
Is the only palaeontological site in Romania where intact fossil remains of Ursus spelaeus were found. There is one cave bear skeleton preserved in anatomical connection. The cave is also very rich in formations and has the most modern tourist installations and facilities of all the tourist caves in Romania.

Băiţa-Bihor Karst area
Old mining area, hiding a very complex endokarst including caves excavated in skarns by hydrothermal solutions. The cave found in the Tony mine is the largest cave of this kind in Romania, with more than 1,5 km development.