There is nothing else in the natural world quite like it. One and a half million wildebeest, two hundred and fifty thousand zebras and countless Thomson’s gazelles moving in a continuous cycle across the plains of Tanzania and Kenya, driven by rainfall and the growth of grass, following a route their ancestors have followed for millennia. The Great Migration is not a single event with a start and a finish. It is a year-round phenomenon, and knowing where to be and when is what separates a remarkable experience from an ordinary one.