Κολούμπο

Kolumbos is an active submarine volcano roughly 7 km northeast of Santorini, part of the Cycladic arc — a northeast-trending tectonic weakness zone linking a chain of volcanic structures from the Christiana Islands to Santorini itself. Its last major eruption in 1650 generated a tsunami and reportedly killed dozens along the nearby coastline. Today the caldera sits at around 500 metres depth and hosts hydrothermal vents with high CO₂ concentrations that sustain extremophile microbial communities, making it an active subject of marine geological research. The shallower flanks are occasionally reached by divers on boat excursions from Santorini.