One of our early landings was at a place called Deception Island, a land mass that was formed by an underwater volcano that was the sight of whaling station until an eruption in the 1960s that destroyed the place. Now it's nothing but ruins and black sand beaches.
I enjoyed walking around the island for a bit to explore some of the ruins in an area that reminded me very much of a moonscape, but the highlight was when people took a swim in the thermal waters. The volcano heats the water in a somewhat dispersed fashion, so if you didn't land in exactly the right space, your swim would be a bit chilly. Still, it was a fun event made even better by the bartender who awaited the swimmers on the beach with a concoction that involved hot tea and whiskey.