U.S. Marines and Sailors practice amphibious landings during Trident Juncture 2018 in Alvund, Norway, Oct. 29, 2018. The Norwegian geography and climate provides a unique training environment for Marines and Sailors to help strengthen forces and enhance combat readiness. U.S. Navy Sailors are among 14,000 participants from the U.S. Army, Marine Corps and Air Force in with 31 NATO allies and partner nations. Trident Juncture 18 is designed to test NATO’s ability to plan and conduct a major collective defense operation – from troop training at the tactical level, to command over large elements of a NATO force. Department of Defense video Allied Joint Forces Command.