Rangers from Zakouma National Park sit on the back of a vehicle as they transport the black rhino to their holding pens on May 4, 2018. The black rhino has been considered officially extinct in the country of Chad since the 1990's but due to an institutional cross-country collaboration between the Chadian and South African governments the black rhinoceros has returned to the country. Through a collaboration between conservation organization African Parks and South African National Parks, six rhinos where flown cross continent to be reintroduced to Zakouma National Park in Chad. / AFP PHOTO / STEFAN HEUNIS