U.S. and Portuguese Marines sit aboard a Marine Corps CH-53E Sea Stallion helicopter flying to participate in a combined helicopter assault training near Pinheiro Da Cruz Beach, Portugal, Oct. 21, 2015, during exercise Trident Juncture 15. The helicopter crew is assigned to the 26th Marine Expeditionary Unit, embarked aboard the amphibious transport dock ship USS Arlington. Trident Juncture is a NATO-led exercise designed to certify response forces and develop interoperability among participating NATO and partner nations. U.S. Marine Corps photo by Sgt. Austin Long