Nisyros

Nisyros, a satellite-island of Kos, can be seen in a single day. You can comfortably visit all three populated towns and two uninhabited ones, stroll the local beaches, dine at seafood restaurants, and even visit the mineral springs and steam cave. Nisyros has one particularly unique attraction that draws tourists to its shores--it’s home to an active volcano. Well, to be more precise, not an active but a dormant one. The last time the volcano “woke up” was in the early 21st century. Now the island’s guests are taking enthusiastic advantage of the opportunity to see with their own eyes all five of its craters, the largest and most famous of which is Stefanos.
The two coastal towns, Mandraki and Pali, are suitable for a visit while in Nisyros. Yachtsmen tend to prefer Pali for its strong winds and powerful waves, and prefer Mandraki for its multiple ferries.