The great mammal migrations that no longer grace the Earth—with millions of pounding hooves and flapping wings—are now the stuff of legend. But they are not all lost for eternity. In South Sudan in Central Africa, an antelope migration like no other is driving possibly millions of White-eared Kob, Tiang (Topi) antelopes, Mongalla Gazelles and Bohor Reedbucks across one of the last and most exceptional wild ecosystems left on Earth.