Nisyros

The volcano on Nisyros has not erupted since 1888, but remains quietly active. The entire island is in fact a volcano, with a 4 km caldera at its center and five smaller craters, the most imposing of which is the 3,000 to 4,000-year-old Stefanos. With a depth of 27m and a 330m diameter, it is considered the largest and most well preserved hydrothermal crater in the world. Like a sleeping beast, it’s still puffing sulphuric fumes from its many fumaroles, making it hard for some people to visit the area.