U.S. Secretary of Defense James N. Mattis and other government and military leaders and guests attend the National Veterans Day Observance at Arlington National Cemetery, Arlington, Va., Nov. 11, 2018. The Secretary of Veterans Affairs Robert L. Wilkie led the wreath-laying ceremony at the Tomb of the Unknown Soldier and delivered the address in the cemetery’s Memorial Amphitheater. (DOD photo by Lisa Ferdinando)