The men of U.S. Air Force Tops in Blue sing together during their performance Aug. 19, 2014, at the Wings Over the Rockies Air and Space Museum in Denver. Tops in Blue is the Air Force's premier entertainment showcase that tours around the world, performing in 20 countries and more than 70 locations in the United States each year. (U.S. Air Force photo by <PERSON> <PERSON>/Released)