A U.S. Air Force F-16 Fighting Falcon assigned to the 555th Fighter Squadron lands at Graf Ignatievo Air Base, Bulgaria, for exercise Thracian Star 21, July 9, 2021. Thracian Star 21 is a multilateral training exercise with the Bulgarian air force, aimed to enhance the ability to rapidly deploy to remote locations and provide a credible force to assure stability for the region. (U.S. Air Force photo by Airman 1st Class Brooke Moeder)