U.S. Air Force F-16 Fighting Falcons assigned to the 555th Fighter Squadron fire munitions at a Graf Ignatievo Air Base range during Thracian Star 21 in Bulgaria. The 555th FS is participating in Thracian Star 21, a Bulgarian air force-led exercise, and will complete air-to-air, air-to-ground, and long range intercept training. (U.S. Air Force video by Airman 1st Class Brooke Moeder) More