Sulphureous cave is the biggest manifesta­tion of hydrothermal phenomenon. The cave is 300 metres long and is possible going by feet for the first 20 metres until a lake. Arriving by boat we clearly smell the sulphydric acid vapours (rotten eggs smell). This area is infact called Calafetente (fetli cove). It's a compelling dive because the sulphureous waters reduced visibility and the narrow pas­sages. I remember this wasn't the easiest sur­vey. A peculiar cave formation called "the tooth" indicates the departure of a 200 mt long tunnel. The walls are completely white and soft for the sulphur bacteria colonies. The massive whitish water flowing at the entrance Is breathtaking. Four divers died here.