F-16 Fighting Falcons and Airmen from the 510th Fighter Squadron at Aviano Air Base, Italy, arrived at Kallax Air Base, Sweden, May 22, 2015, for Arctic Challenge Exercise 2015. Nine nations participated during the exercise to help ensure interoperability, and strengthen relationships and engagements with NATO allies and Partners for Peace. (U.S. Air Force photo/Staff Sgt. Evelyn Chavez)