Video: Swimming with Icebergs

You don't typically think of swimming as an "extreme" sport, but in this video we're introduced to some swimmers who just might change your mind. The clip features Stig Severinsen, a world-class free diver who can stay submerged with just a single breath for minutes at a time. He then uses this ability to go swimming under icebergs, creating a scene that is unlike any you've seen before. The first part of the video, which comes our way courtesy of National Geographic, discusses how Stig, and other swimmers, are able to control their bodies as they prepare for the conditions they'll face in the cold water. But later, it transitions to just watching him swim through these glass-like structures. It is amazingly beautiful to behold.