The volcano is the most impressive attraction of Nisyros with a three kilometer long caldera and various craters with that of Agios Stefanos being the major one, as it is one of the largest in the world with a diameter of 260 meters and 30 meters depth. The last notable eruption occurred in 1888, since then the volcanic activity is limited to fumaroles gases reaching the surface through cracks, while the smell from the sulfur is strong. We suggest wearing closed shoes.