Six B-1 bombers sit silently on the aircraft parking area on the first evening of an Operational Readiness Exercise at Ellsworth Air Force Base, S.D., March 14, 2012. The B-1s had been prepared for a series of exercises designed to test the base’s ability to process and mobilize personnel, aircraft and associated equipment. (U.S. Air Force photo by Airman 1st Class Zachary Hada/Released)