As tensions with Russia in the Arctic rise, U.S. Special Forces have been prepping for the future or war in the high north in Sweden. WSJ's Sune Rasmussen joined U.S. Green Berets in a grueling Arctic training camp to understand why subzero survival skills are crucial for the future of war. He was the first civilian to take part in this training, having to ski through the woods with a heavy rucksack, take an ice plunge in freezing water, camp overnight on his own and more. #Military #Arctic #WSJ