U.S. Air Force Senior Master Sgt. Joel Remsnyder, 555th Aircraft Maintenance Unit weapons section chief, middle, teaches armament system familiarization procedures to Bulgarian air force members on a U.S. Air Force F-16 Fighting Falcon assigned to the 555th Fighter Squadron at Graf Ignatievo Air Base, Bulgaria, July 16, 2021. More than 150 Airmen and eight F-16s assigned to the 555th FS participated in Thracian Star 21, a Bulgarian air force-led exercise aiming to enhance interoperability and the ability to rapidly deploy to remote locations. (U.S. Air Force photo by Airman 1st Class Brooke Moeder)