Eight surviving veterans of the 509th Composite Group along with their friends and family listen to a South Dakota Air and Space Museum tour guide explain the outdoor elements of the decommissioned training Minuteman missile silo at Ellsworth Air Force Base, S.D., Sept. 28, 2011. The veterans were visiting the base during their annual week-long reunion, which has been happening for more than 20 years. (U.S. Air Force photo by Tech. Sgt. Nathan Gallahan/Released)