It is about 3610 m long overall and about 2 kilometres of it can be visited the year round, although tourists have to be accompanied by guides
The G.B. Trener or Calgeron cave is located on the orographic right hand side of the Brenta river and can be reached on foot in about half an hour from the road leading to Selva di Grigno. It is about 3610 m long overall and about 2 kilometres of it can be visited the year round, although tourists have to be accompanied by guides. The rest of the cave is accessible only to experts with the necessary equipment and only in winter. It consists of a series of caves, entirely dug in the dolomite, and includes 11 interesting lakes, an extraordinary series of basins made up of snow-white concretions forming a flight of steps, and an extremely imposing and spectacular 80-metre-long cave. Particularly remarkable is the seventh lake, which is over 40 metres long and 4 metres deep. A thick layer of white clay, found in a side channel, is probably a consequence of the Riss glaciation. Therefore, the mud could date back to 250,000 years ago.