India, March 31 -- Sailing above the Arctic Circle is like discovering an entirely new world: a place where narwhals swim between fjords, the sky flickers with dancing lights, and centuries-old Inuit communities have learned to thrive. By Maggie Shipstead

I'm not sure

I've ever experienced sharper regret than in the fraction of a second between leaping from a boat platform and hitting the surface of the Arctic Ocean. The drop was only six feet or so, but that was long enough for my brain to respond to the sight of dark, ice-strewn water flying up to meet me by shrieking, "You should not have done this!" Too late. I was doing a polar plunge.

I was on the Silver Cloud, a Silversea Cruises expedition ship that carries 254 passengers thoug...