Its vertiginous height of 270 metres makes su Sterru Europe’s deepest single-span chasm. Formed in the heart of the Golgo plateau (400 metres high), within the Baunei territory, the chasm is a place filled with mysteries and ancient legends that will give you goose bumps: according to legend, it was once a snake’s lair (su scultone), whose menace was warded off by the building, in the 17th century, of the church of San Pietro nearby. The cavity is actually the habitat of the tame Sardinian cave salamander, an amphibian adapted to this location, accompanied by the porrohomma spider and a few terrestrial crustaceans. The chasm was initially believed to be a volcano (in old topographic maps it was identified as “Old Crater”) 100-150 metres deep, but its complete exploration, in 1957, revealed the enormous karstic abyss created by erosion. Sterru, in fact, means both “descending slope” and “pit”, and is a term commonly used to other place names in Ogliastra and Barbagia. Today, it is only explored by experienced speleologists.