181017-N-WO404-139 KEFLAVIK, Iceland (Oct. 17, 2018) U.S. Marines, assigned to the 24th Marine Expeditionary Unit, embark a CH-53 Super Stallion helicopter, during a simulated air assault as part of exercise Trident Juncture 2018 in Keflavik, Iceland, Oct. 17, 2018. Trident Juncture, a NATO-led exercise, hosted by Norway, will include around 50,000 personnel from NATO countries, as well as Finland and Sweden, and will test NATO’s collective response to an armed attack against one ally, invoking Article 5 of the North Atlantic Treaty. (U.S. Navy photo by Mass Communication Specialist 2nd Class Jonathan Nelson/Released)