The First Sea Lord and Chief of Naval Staff of the British Royal Navy, Adm. Sir George Zambellas, right, prepares to board a U.S. Marine Corps MV-22 Osprey tiltrotor aircraft from Marine Helicopter Squadron 1 (HMX-1) at the Pentagon in Arlington, Va., July 29, 2014. Zambellas is taking part in the Commandant of the Marine Corps' Counterpart Program, which invites foreign military leaders to visit the United States and interact with U.S. military leaders. (U.S. Marine Corps photo by Cpl. Michael C. Guinto/Released)