While I was on a whale-watching trip out of Akureyri, Iceland in late June, a humpback whale approached our boat and began vigorously slapping its tail and pectoral fins on the water. The humpback was breathtakingly close to us, and the dramatic behavior lasted for more than five minutes.

Check it out in the video I shot above. (Please accept my apologies for the distracting wind noise — I was not equipped at the time with an external mic and windscreen.)