US President Barack Obama walks down the stairs as he disembarks from Air Force One upon his arrival at the Tan Son Nhat airport in Ho Chi Minh City on May 24, 2016. Obama told communist Vietnam on May 24 that basic human rights would not jeopardise its stability, in an impassioned appeal for the one-party state to abandon authoritarianism. / AFP PHOTO / CHRISTOPHE ARCHAMBAULT