U.S. Air Force Col. John J. Allen Jr., 633rd Air Base Wing commander, helps children from the Langley Child Development Center plant a tree to celebrate Earth Day and Arbor Day at Langley Air Force Base, Va., April 25, 2013. The tree planting ceremony was one of several events that took place to celebrate Earth Day. (U.S. Air Force photo by Senior Airman Kayla Newman/Released)