A U.S. flag is flown on the 36th Operation Support Squadron air traffic control tower during a September 11 memorial stair climb event on Andersen Air Force Base, Guam, Sept. 11, 2019. Today marks the 18th anniversary of the deadliest terrorist attack on American soil. The 36th Civil Engineer Squadron fire department hosted a memorial ceremony followed by a memorial stair climb event to honor the 343 fire fighters, 60 police officers, eight paramedic, and one New York fire patrolman who paid the ultimate sacrifice that day. (U.S. Air Force photo by Staff Sgt. Divine Cox)