The most important spring of Sardinia (300 litres/second on average) has formed a deep pool between high rocky walls. Its water, channelled by the karstic Supramonte, is incredibly pure, explaining its popularity with pot-holers-divers. Surrounded by eucalyptus, the spot was declared a "natural monument" and is in the heart of a national park, where many trails lead to the peaks of the Gennargentu.