Senior Master Sgt. Phillip E. Krzywicki, United States Air Force Concert Band French hornist, plays during a flash mob at the Smithsonian National Air and Space Museum Udvar-Hazy Center in Chantilly, Va., Dec. 2, 2014. The approximately six-minute flash-mob performance concluded with the playing of “Carol of the Bells” by Mykola Leontovych. (U.S. Air Force photo/ Senior Airman Nesha Humes)