Image 0 of 7Marine Corps Gen. Joe Dunford, chairman of the Joint Chiefs of Staff, speaks at the Semper Fidelis Society Boston Marine Corps birthday luncheon in Boston, Nov. 13, 2017. (Sgt. James K. McCann/Army) Marines collect sand on Iwo Jima, Japan, Nov. 7, 2017, as part of an educational program on the site’s historical significance. The Marines are assigned to Marine Corps Air Station Iwakuni. (Lance Cpl. Mason Roy/Marine Corps) Seaman Joanna Valdez, assigned to the deck department aboard the San Antonio-class amphibious transport dock ship USS San Diego (LPD 22), fires an M4A1 Carbine during a live-fire training exercise on the ship’s flight deck. (Justin A. Schoenberger/Navy) Air Force Senior Airman Adam Armstrong places a cover over a tube on an F-16CM Fighting Falcon after a combat capability demonstration at the Dubai Airshow in Dubai, United Arab Emirates, Nov. 11, 2017. (Staff Sgt. Zade Vadnais/Air Force) Sgt. Rocky, 3rd Infantry Division's mascot, jumps over obstacles with a group of Dog Face Soldiers during a Marne Mile competition Nov. 13, 2017, at Fort Stewart, Ga. Teams of four competed to achieve the fastest time through the obstacle course while completing basic soldier tasks. (Sgt. Caitlyn Smoyer/Army) The Arleigh Burke-class guided-missile destroyer USS Donald Cook (DDG 75) transits the Mediterranean Sea during exercise Dogu Akdeniz 2017. (Theron J. Godbold/Navy) A U.S. Marine with Marine Wing Support Detachment 31 inspects an aircraft while conducting mission rehearsals for an aircraft salvage and recovery exercise during Integrated Training Exercise (ITX) 1-18 aboard Marine Corps Air Ground Combat Center, Twentynine Palms, Calif., Nov. 7, 2017. (Staff Sgt. Kowshon Ye/Marine Corps)