President Barack Obama shakes the hand of Senior Airman Katie Spencer, a Joint Base Andrews Nuclear Security Summit Media Operations Center media escort, during an impromptu stop to thank military and civilian team members for their work supporting his summit April 9 through Thursday. Airman Spencer is a Reserve augmentee in the 316th Wing Public Affairs Office from the 482nd Fighter Wing, Homestead Air Reserve Base, Fla. The president walked to the fence line adjacent to the flight line before boarding Air Force One to fly to Cape Canaveral, Fla. (U.S. Air Force photo by Bobby Jones)