150918-N-AT895-954 ANNAPOLIS, Md. (Sept. 18, 2015) Adm. Jonathan Greenert and his wife walk through sideboys after his retirement and change of command ceremony held at the U.S. Naval Academy. Greenert became the 30th Chief of Naval Operations Sep. 23, 2011. He is relieved as CNO by former Director, Naval Nuclear Propulsion Adm. John Richardson. (U.S. Navy photo by Mass Communication Specialist 1st Class Nathan Laird/Released)