Nea Kameni Crater

One of the only places in Europe where divers can descend alongside an active submarine volcanic feature. Warm hydrothermal vents at 10 to 18 m release continuous streams of gas bubbles and heat the surrounding water by 3 to 5 degrees above ambient. The lava formations are raw and angular compared with older reef structures: black basalt fingers and sulphur-stained vents colonised by tube worms and thermophilic algae. Marine life is sparse but bizarre, adapted to the chemical gradient around each vent.