The Arctic is becoming a training ground for the US military. You want to prepare for future dangers.

The cold presents special challenges. The Arctic is warming four times faster than the rest of the world. The Pentagon has broadened its focus on what a war in one of the most dangerous areas on earth might look like - and how its most sophisticated units can counter a direct threat of the US homeland. Here, says Capt. Bill Gallagher, who commands the SEAL unit involved in the exercise, called the Arctic perhaps the harshest and most extreme place in which a military can operate. The sobering realization was that any conflict in the far north would be an absolute nightmare for those tasked with fighting it. This winter, The Washington Post was given rare access to teams of SEALs, Green Berets, the 160th Special Operations Aviation Regiment and other elite soldiers. It's a windswept outpost on the state's southern coast, and in the barren training grounds outside the city of Fairbanks.