Bossea Cave is located in Corsaglia Valley, in the municipality of Frabosa Soprana, at 836 meters above sea level, and it is one of the most beautiful and important caves in Italy. It is a protected area managed by Marguareis Natural Park.

It is characterized by remarkable environmental dimensions, with vast panoramas on picturesque and steep landscapes; a great richness of running waters and precipices; it has a high scientific and naturalistic value.
Ideally, it can be divided into a lower zone, characterized by imposing dimensions, and an upper zone consisting of a complex of narrow galleries developed on overlapping planes. The two parts of the cavity are separated by the waterfall of the Ernestina Lake. The calcareous concretion consisting of stalactites, stalagmites, curtains and flows often presents impressive dimensions and great beauty for shapes and colors.
The cave has 57 species of cave animals, 10 of which are endemic, and great interest is held by the paleontological material revealed by excavations conducted for several decades since June 1865. With part of the material was reconstructed a complete skeleton of Ursus Spelaeus, exposed in the Temple Hall.
In the cave there is a constant temperature, all year round, of 9 ° C: it is recommended, therefore, to address the excursion with appropriate clothing (non-slip shoes and sweater or sports jacket).