A wreath stands in honor of the 15th anniversary of the attacks on Sept. 11, 2001, at the Mount Rushmore National Memorial, S.D., Sept. 11, 2016. Defense officials from more than 30 countries conducted a wreath laying ceremony in remembrance of the attacks that occurred in New York, Virginia and Pennsylvania. (U.S. Air Force photo by Senior Airman Anania Tekurio)