Obama departs on trip to Vietnam, Japan

File picture of Barack Obama and Michelle Obama walking to their limousine at Andrews Air Force Base in Maryland on March 25, 2016, upon their return from a four-day trip to Cuba and Argentina. AFP / NICHOLAS KAMM Andrews Air Force Base, United States: Barack Obama departed Saturday on a trip to Vietnam and Japan that will include the first visit to Hiroshima, site of the world's first nuclear attack, by a sitting US president.