Chairman of the Joint Chiefs of Staff Gen. Martin E. Dempsey, and his wife Deanie stand as U.S. President Barack Obama, accompanied by Maj. Gen. Jeffrey S. Buchanan, commander of the U.S. Army Military District of Washington, lays a wreath at the Tomb of the Unknowns, on Memorial Day, Monday, May 25, 2015, at Arlington National Cemetery in Arlington, Va. (DoD photo by Mass Communication Specialist 1st Class Daniel Hinton/released)