181017-M-PR541-726 KEFLAVIK, Iceland (Oct. 17, 2018) A U.S. Marine assigned to the 24th Marine Expeditionary Unit (MEU) posts security at Keflavik Air Base in Iceland, Oct. 17, 2018, during Exercise Trident Juncture 18. Trident Juncture training in Iceland promotes key elements of preparing Marines to conduct follow-on training in Norway in the later part of the exercise. (U.S. Marine Corps photo by Lance Cpl. Menelik Collins/Released)