The thirds part separates from the first tour about one hundred metres from the entrance, in correspondence to the lake-siphon, through a branch called "Tunnel of Wonders". The beginning is formed by two parallel tunnels, full of erosive shapes, that lead into a room characterised by a striking reddish flowstone hanging on a wide shaft. From the top of which an impressive view of the "Main Gallery", can be seen fifteen metres below. Once past a narrow part, we enter a second room, much wider than the first, full of sparkling stalactites, stalagmites and flowstones.

Beyond this point, the appearance of the cave changes abruptly: after climbing a few steps, we reach the bottom of a huge vertical shaft (Shaft of Infinity) where the formations almost entirely disappear, making place for a grim and fascinating environment. The eye meets with the bare walls of the shaft, interrupted here and there by the dark entrances to side passages. Here the path temporarily abandons the shaft, proceeding by flights of stairs, to the inside of a vertical crevice decorated with pretty formations. After a flat part, the path reaches the shaft again by means of a small bridge suspended twenty four metres from the bottom. The view is stunning and in particular the effect of water drops falling against the light call to mind a shower of diamonds.

Further on the path continues along jagged walls until it reaches a point where the shaft is divided in two by a natural arch formed by the erosion made by ancient waterfalls, which even nowadays become noisily active when outside there is persistent heavy rainfall.

Once again we leave the vertical surroundings to visit a small, flat, richly-coloured branch that is characterised by a morphology caused by rockfall. This is a diversion of only a few steps since, immediately after, we face the shaft again, climbing up thirty metres over two small bridges which enable us to reach the big room on the opposite side. From here a staircase takes us up the shaft again, where it's possibile to see the bottom from a height of over forty metres.

A few more steps and we enter the "Hall of Infinity", whose entire ceiling is carved by a narrow winding bend caused by the regression of an ancient waterfall that was once flowing into the shaft from a height of seventy metres.

Crossing the hall, the tour ends in a gorge where, after heavy rainfall, a fierce waterfall can be admired.

Back down a the bottom of the shaft, we cross the "Hall of Wonders" and reach the "Main Gallery" of the first tour near the "Crystal Lake" going down a wonderful corridor crossing through forests of white stalactites and stalagmites.

The third tour enables visitors to do a complete tour of the parts of the cave equipped for the public and also includes the first and second tours.