U.S. Education Secretary <a gi-track='captionPersonalityLinkClicked' href=/galleries/search?phrase=Arne+Duncan&family=editorial&specificpeople=3049193 ng-click='$event.stopPropagation()'>Arne Duncan</a> speaks to students at School Without Walls August 27, 2013 in Washington, DC. Duncan participated in an event to discuss '50 Years of Struggle: Youth Driving Economics, Education, and Social Change,' which was to mark the 50th anniversary of Dr. Martin Luther King Jr.'s 'I Have a Dream' speech.