U.S. Marine Lance Cpl. Zane Harmon fast ropes from a tower aboard Marine Corps Base Hawaii, May 12, 2015. Harmon is part of the 15th Marine Expeditionary Unit’s Maritime Raid Force security element. These Marines practice fast roping to ensure they are prepared for any type of mission during deployment. (U.S. Marine Corps photo by Cpl. Anna Albrecht/Released) - U.S. Marine Lance Cpl. Zane Harmon fast ropes from a tower aboard Marine Corps Base Hawaii, May 12, 2015. Harmon is part of the 15th Marine Expeditionary Unit’s Maritime Raid Force security element. These Marines practice fast roping to ensure they are prepared for any type of mission during deployment. (U.S. Marine Corps photo by Cpl. Anna Albrecht/Released)

Marines load a diver propulsion device into a combat rubber raiding craft Sept. 20 at U.S. Naval Base Guam during Exercise Valiant Shield 2014. The device aids the Marines conducting night infiltration. Valiant Shield is a U.S.-only exercise integrating Navy, Air Force, Army, and Marine Corps assets, offering real-world joint operational experience to develop capabilities, which provide a full range of options to defend U.S. interests and those of its allies and partners. The Marines are reconnaissance men with 3rd Reconnaissance Battalion, 3rd Marine Division, III Marine Expeditionary Force. - Marines load a diver propulsion device into a combat rubber raiding craft Sept. 20 at U.S. Naval Base Guam during Exercise Valiant Shield 2014. The device aids the Marines conducting night infiltration. Valiant Shield is a U.S.-only exercise integrating Navy, Air Force, Army, and Marine Corps assets, offering real-world joint operational experience to develop capabilities, which provide a full range of options to defend U.S. interests and those of its allies and partners. The Marines are reconnaissance men with 3rd Reconnaissance Battalion, 3rd Marine Division, III Marine Expeditionary Force.