These Ice Swimmers Battle Frozen Death with Every Stroke | That's Amazing

High in the mountains of southern Africa, 15 swimmers compete in one of the most extreme—and chilling—races on earth. With no wet suits or protection, they swim one kilometer in water that is cold enough to kill them. For these athletes, it's not just a battle to the finish, every stroke is a battle to stay alive. Tune in to "That's Amazing" every Sunday at 9pm on The Weather Channel.