Nigerian President Mohammadu Buhari raises his fist to greet the crowd before taking oath of office at the Eagles Square in Abuja, on May 29, 2015. Buhari, 72, defeated Jonathan in March 28 elections -- the first time in Nigeria's history that an opposition candidate had beaten a sitting president. AFP PHOTO/PIUS UTOMI EKPEI (Photo credit should read PIUS UTOMI EKPEI/AFP/Getty Images)
