Herro Mustaf, U.S. Ambassador to the Republic of Bulgaria, sits in the cockpit of a U.S. Air Force F-16 Fighting Falcon during Thracian Viper 20 at Graf Ignatievo Air Base, Bulgaria, Sept. 24, 2020. Thracian Viper 20 is a multilateral training exercise with the Bulgarian air force, aimed to increase operational capacity, capability and interoperability with Bulgaria. (U.S. Air Force photo by Airman 1st Class Ericka A. Woolever)