U.S. Air Force Gen. Terrence J. O'Shaughnessy, center, Pacific Air Forces commander, Gen. Yoshiyuki Sugiyama, right, Japan Air Self-Defense Force chief of staff and Pilot Maj. Gen. Sudheer Shrestha, Nepal chief of army aviation, receive a historic brief during a boat tour of Pearl Harbor, Hawaii, Sept. 26, 2017. The historic tour of the harbor is part of the 2017 Pacific Air Chiefs Symposium that brings together air chiefs from across the Indo-Asia-Pacific region to discuss regional challenges and goals, maintaining rules based international order in the Pacific and increasing interoperability with allies and partners. (U.S. Air Force photo by Tech. Sgt. Eric Donner)