Senior Airman Giuseppe Santillo, 379th Expeditionary Civil Engineer Squadron firefighter, rings a bell to honor the lives lost during the 9/11 Memorial Ceremony at Al Udeid Air Base, Qatar, on Sept. 11, 2019. Ringing the bell symbolizes death in the line of duty. The “Four Fives” tradition, also referred to as the “5-5-5-5” code, was adopted from New York firefighters and has been used in firehouses since 1865. (U.S. Air Force photo by Staff Sgt. Ashley L. Gardner)