The air current lets visitors know in advance the extension of the cavity they are about to walk through. The entrance goes into a wide elliptical gallery whose walls show evident signs of quite recent erosion. You then cross a room where, during work to build the paths, numerous bones of the Cave Bear were found. It's followed by potholes and another elliptic gallery that divides into two branches above one another. The bottom completely submerges into the water of a siphon, the top one, man-made, allows visitors to pass the flooded part at all times. A little further on the siphon re-emerges forming a deep pool of emerald green water.

Passing on the left the entrance to the "Tunnel of Wonders" you proceed along a gallery rich in formations ("Main Gallery") until you reach a mirror of water ("The Crystal Lake") which reflects a white column formed by the joining of stalactites and stalagmites.

Proceeding past a lower part you enter the unforgettable "Pendant Room", where big, slender , transparent polychrome draperies are flanked by flowstones with shiny colours and bizarre twisted stalactites. The floor is completely covered by massive stalagmite formations.

The "Hall of Collapse" follows, a room more than twenty metres high with impressive yellow and orange flowstones that cover and cement a pile of rocks that collapsed down from the ceiling in ancient times. It's possible to distinguish amongst these harmonious forms of erosion some real groups of sculptures created by the imagination of Mother Nature.

Further on, past the magnificent flowstone called the "Pink Chimney", the path crosses the "Monument Room" and the "Tunnel of Draperies", passes the entrance to the "Intermediate Tunnel", the way back from the second tour, and reaches the bottom of a big 40-metre shaft, whose walls are mostly covered in formations ("Hall of 30 metres"). During floods, a noisy waterfall comes poring down into a dark crevice flanked by big flat stalagmites.

Proceeding the path goes up a steep flight of stairs towards the "Pass", which after going down about twenty steps, you stop on the edge of the "Giants' Abyss", where the first tour ends.