Starting with a single cellist on the floor of the National Air and Space Museum’s Milestones of Flight gallery and and growing to 120 musicians, The United States Air Force Band unleashed their first-ever flash mob and left museum visitors.

This video originally made its debut December, 3 2013  but has made its way back in to circulation as the holiday’s approach.

The four-minute performance featured an original arrangement of “Jesu, Joy of Man’s Desiring/Joy to the World,” led by the Band’s commander and conductor, Col. Larry H. Lang.

As you would expect everyone was totally shocked including tourists and school groups as instrumentalists streamed into the gallery from behind airplanes and space capsules, and vocalists burst into song from the Museum’s second floor balcony.

Seriously, the kids faces are priceless!