A KC-135 Stratotanker assigned to the 134th Air Refueling Wing out of McGhee Tyson Air National Guard Base, Knoxville, Tenn., sits on the flight line under the Aurora Borealis during Exercise Trident Juncture 18 at Kallax Air Base, Sweden, Nov. 5, 2018. The exercise takes place in Norway and the surrounding areas of the North Atlantic and the Baltic Sea, including Iceland and the airspace of Finland and Sweden. With more than 50,000 participants from 31 countries, it is the largest NATO exercise since 2002. (U.S. Air Force photo by Staff Sgt. Jonathan Snyder)