150511-N-AT895-227 WASHINGTON (May 11, 2015) Chief of Naval Operations (CNO) Adm. Jonathan Greenert and retired Adm. James Holloway, former CNO, look through a commemorative book during the centennial celebration for the office of the Chief of Naval Operations and Navy staff at the Washington Navy Yard. (U.S. Navy photo by Mass Communication Specialist 1st Class Nathan Laird/Released)