Pothia and Massouri are the main tourist spots in Kalymnos, Personally, I prefered Pothia as it has more things to see. The Venetian Castle and the windmills on the way to the castle were just lovely. I also enjoyed much the workshops of the spongers, it was a unique thing to see that you hardly meet it in other places. A nice man was there and explained us in mediocre English the history and the old process of sponge-diving. I only regreted that I didn't do climbing on Kalymnos, it is a pity I am afraid so much of heights, because the landscpaes were trully wild.