The caldera of Nisyros, the central crater of the island’s volcano, is a landscape of exceptional geological and natural interest and forms part of the European Natura 2000 network of protected areas.
With a diameter of approximately 4 kilometres, the rim of the caldera rises to elevations ranging from 250 to 600 metres, while its floor lies about 100 metres above sea level.
Within the caldera lies the impressive “Stefanos” hydrothermal crater, where fumaroles, hot gases and distinctive volcanic rocks bear witness to the geological activity that continues to shape the island. A rare natural monument and a living window into the formation and evolution of the Aegean.