U.S. Air Force Maintainers from the 2nd Bomb Wing look on as a B-52 Stratofortress starts their engines on Barksdale Air Force Base, La. April 1, 2015. The B-52, manned by aircrew from the 307th Bomb Wing is part of Exercise “Polar Growl.” These aircraft will conduct simultaneous, long-range sorties from Barksdale to the Arctic and North Sea regions. Bomber missions such as these ensure bomber crews maintain a high state of readiness and proficiency and demonstrate their ability to provide a flexible and always-ready global-strike capability. (U.S. Air Force photo by Master Sgt. Dachelle Melville/Released)