Commandant of the Marine Corps Gen. Robert B. Neller cuts the cake Nov. 9, 2015, at the Pentagon during a ceremony celebrating Corps' 240th birthday. (Lena Wakayama/U.S. Marine Corps)

Marines and sailors with Company E, Battalion Landing Team 2nd Battalion, 6th Marines, conduct close-quarter firing drills in the Gulf of Aden aboard the USS Oak Hill, Nov. 7, 2015. (Bobby Yarbrough/U.S. Marine Corps)

Marines from 1st Marine Division, Company A, 3D Amphibious Assault Battalion conducts Amphibious Assault Vehicle qualifications tables 1-9 for the first time at Yuma Proving Grounds, Ariz., on Nov. 7, 2015. (AaronJames Vinculado/U.S. Marine Corps)

Marines from Marine Forces Reserve return from a 3-mile motivational formation run led by Sgt. Maj. Michael J. Rowan, center, and Col. Steven G. Godinho at Marine Corps Support Facility, New Orleans, Nov. 10, 2015. (Gabrielle Quire/U.S. Marine Corps)

U.S. Marines and sailors with the 15th Marine Expeditionary Unit provide security during a mass-casualty drill on the flight deck of the USS Essex, Nov. 4, 2015 in the Arabian Sea. (Elize McKelvey/U.S. Marine Corps)

Marines with the Silent Drill Platoon perform at the Minnesota Vikings game, Nov. 8, 2015 in Minneapolis, Minn. (Martin Egnash/U.S. Marine Corps)

After being gassed, a Marine with Company K, 3rd Battalion, 3rd Marine Regiment, guides Marines through concertina wire during training exercise Lava Viper, a staple of their pre-deployment training, at Range 10 at Pohakuloa Training Area, Hawaii, Nov. 4, 2015. (Harley Thomas/U.S. Marine Corps)

A Marine with Transportation Services Company, Combat Logistics Battalion 2, carries a simulated casualty to an MV-22 Osprey for a medical evacuation during a live-fire vehicle recovery exercise as part of Integrated Training Exercise 1-16 at Marine Air Ground Combat Center Twentynine Palms, Calif., Nov. 4, 2015. (Tia Nagle/U.S. Marine Corps)