a radioman on a C-54 out of Iceland and on my very last flight, Keflavik to Germany, the pilot took us out off the coast, and circled some smoking, bubbling place out in the ocean just offshore.
It was to become the island of Surtsey, which is now inhabited. Of course, then it was just big smoking bubbles erupting from the ocean. Still rather impressive from 3-4 thousand feet!
That's a cool thing though. Wasn't that report in some sailing mag a while ago? Seems I recall an article about someone sailing through floating rocks.