volcanic caldera crater stefanos - view from above. island of nisyros, greece.

above active activity attraction caldera cauldron cave cavity chamber collapse collapsed crater craters danger depression destination destruction earthquake eruption eruptive europe exploration explosion explosive force geological geology greece greek hole island lava magma mediterranean mountain natural nisyros power ring rock scenery seismic shapes smoke south southern special stages steam stefanos stone sulfuric tourism tourist unrest vent vents view visit volcanic volcano