A Marine with 4th Light Armored Reconnaissance Battalion, 4th Marine Division, conducts live fire drills during exercise Trident Juncture 2015 in Almeria, Spain, Oct. 27, 2015. Trident Juncture is the largest exercise NATO has held in the past 10 years with more than 30 nations and more than 5,000 U.S. service members participating. NATO is showing the world how they operate as a global response force with multiple nations in the mix. - A Marine with 4th Light Armored Reconnaissance Battalion, 4th Marine Division, conducts live fire drills during exercise Trident Juncture 2015 in Almeria, Spain, Oct. 27, 2015. Trident Juncture is the largest exercise NATO has held in the past 10 years with more than 30 nations and more than 5,000 U.S. service members participating. NATO is showing the world how they operate as a global response force with multiple nations in the mix.