US President Barack Obama (2-R) is greeted by his half-sister Auma (2-L) as he walks with Kenyan President Uhuru Kenyatta upon arrival on Air Force One at Kenyatta International Airport in Nairobi, Kenya, July 24, 2015. Obama arrived in Africa on a five-day tour with stops in his father's homeland of Kenya, before traveling to Ethiopia. AFP PHOTO | TONY KARUMBA