U.S. Air Force aircrew from the 307th Bomb Wing and aircraft maintenance Airmen from the 2nd Bomb Wing run last minute checks on their B-52 Stratofortress before leaving in support of Exercise “Polar Growl” on Barksdale Air Force Base, La. April 1, 2015. These aircraft will conduct simultaneous, long-range sorties from Barksdale to the Arctic and North Sea regions. These bomber operations provide a flexible and visible signal that highlights the U.S. ability to deter strategic attacks and respond to any potential future crisis or challenge. (U.S. Air Force photo by Master Sgt. Dachelle Melville/Released)