Military in pictures, December 2016 (31 images)

Scarlett Johansson and Chris Evans perform for service members during the USO Holiday Tour at Incirlik Air Base, December 5, 2016. Marine Gen. Joseph F. Dunford, Jr., chairman of the Joint Chiefs of Staff, and USO entertainers, will visit service members who are deployed from home during the holidays at various locations across the globe. Photo by Dominique A. Pineiro/DoD/UPI

U.S. President Barack Obama and Japanese Prime Minister Shinzo Abe present wreaths at the USS Arizona Memorial to honor the service members killed during the December 7, 1941 attacks on Pearl Harbor on December 27, 2016. Abe is the first Japanese prime minister to visit the USS Arizona Memorial. Photo by Jay M. Chu/U.S. Navy/UPI

Scarlett Johansson and Chris Evans sign autographs for service members during the USO Holiday Tour at Incirlik Air Base, December 5, 2016. Marine Gen. Joseph F. Dunford, Jr., chairman of the Joint Chiefs of Staff, and USO entertainers, will visit service members who are deployed from home during the holidays at various locations across the globe. Photo by Dominique A. Pineiro/DoD/UPI

Cpl. Keaton Ohlsen, from Rapid City, South Dakota and assigned to Martial Arts Instructor Course 1-17, conducts squad push-ups during a MAIC aboard Marine Corps Base Hawaii, December 15, 2016. MAIC is a three-week long course that put applicants through rigorous training designed to instill teamwork and develop leadership abilities necessary for a Marine Corps Martial Arts Program instructor to instruct classes. Photo by Sgt. Brittney Vella/U.S. Marine Corps/UPI