Defense Secretary Jim Mattis greets Marc Knapper, U.S. Embassy Seoul deputy chief of mission, as he arrives at Osan Air Base, Republic of Korea, Feb. 2, 2017. The visit, which is Mattis’ first official visit to a foreign country as secretary of defense, highlighted the common traits and strengths shared by the U.S. and ROK governments, including the commitment to bi-lateral cooperation in keeping regional safety and stability in check. (U.S. Air Force photo by Staff Sgt. Jonathan Steffen)