The “Is Janas” cave of Sadali, together with the ancient town, is one of the main tourist attractions in the area: it stretches for around 250 metres through five visitable rooms, all of them highly concretionised. Water plays a key role here: one drop after another has, for around five million years, formed the limestone rock giving it these different, delightful shapes. The spectacle that opens up to the visitor is one of imposing stalactites hanging from the ceiling, large stalagmites and limestone columns which reflect in natural lakes produced by the penetrating rainwater.
The fauna living in the Is Janas cave consists mainly of small, cave dwelling insects, as well as bats and European cave salamanders (known as Speleomantes Imperialis), an unusual and wary cave amphibian.