It is one of the deepest single-span chasms in all of Europe: we are talking about the natural monument Su Sterru (S’Isterru in Sardinian), a gorge of karst origin that suddenly opens on the Golgo di Baunei plateau in Sardinia.
It is located 400 meters above sea level and is 270/280 meters deep with a diameter ranging from 25 to 40 meters. The most superficial part of the sinkhole is made up of black basaltic rocks, the remainder of white limestone rocks.
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The first to lower himself into the chasm was the speleologist Bruno Piredda, but 150 meters of rope were not enough to reach the bottom. On the second attempt, a young architecture student passionate about speleology volunteered, a 22-year-old from Nuoro belonging to the “Gruppo Grotte Nuorese” named Umberto Pintori, who at 10.30am on 25 July 1957 managed to reach the bottom of “Su Sterru”.
Subsequent measurements established that it was one of the deepest single-span chasms in Europe: 280 meters. Since then, descending along the walls of “Su Sterru” has become a “must” for speleology lovers, and many speleo groups have arrived from all over Italy to challenge this legendary abyss.
One of these associations, the “Faentino Speleological Group”, organized an expedition in 1978 and, on that occasion, also allowed a passionate speleologist from Baunei to descend along the vertical shaft: Paolo Muggianu, twenty-six years old at the time, the first local inhabitant to have had the courage to face the mysterious sinkhole of “Su Sterru”.
The walls were photographed meter by meter by a group of biologists who studied their flora and microfauna, including the Sardinian geonewt, the Porrohomma spider and terrestrial crustaceans of the Trischoniscus genus.
Originally it was thought that the chasm was the mouth of a volcano, its entrance was marked as Old crater; it was hypothesized that the black lava covering the Golgo had come out from here but, the intervention of the speleologists revealed that it had been created by normal erosion phenomena and specifically, by the collapse of part of the basaltic walls overlying the limestone rock.
Ancient legends narrated by the scholar Dolores Turchi revolve around Su Sterru, according to which a snake lived inside the cave and girls were offered to appease it. Next to the chasm there is a steel cross placed by the father of Antonio Carta, the young man who fell into the sinkhole on 31 July 1976 in an attempt to photograph the inside.
Today the chasm is a real tourist attraction, a “Natural Monument” since 1993, which attracts thousands of visitors, so much so that “Golgo”, the name of the entire plateau, is now perceived by many as the name of the cavity itself.
The chasm is visible and can be reached in part from the Golgo plateau, but it cannot be used as a tourist cave with an internal route: access to the bottom is permitted only to specialized speleologists.
