Two members of the Republic of Korea Marine Corps carry a roll of concertina wire across Dogu Beach near the South Korean port city of Pohang, April 6, 2017, as they help prepare for Operation Pacific Reach Exercise 2017. The exercise, also known as OPRex17, is a bilateral training event designed to ensure readiness and sustain the capabilities which strengthen the ROK-U.S. alliance. (Combined Forces Command photo by Sgt. 1st Class John Queen/released)