Each year, vast herds of wildebeest, joined by zebra and gazelle, move through the Serengeti–Mara ecosystem, which reaches from northern Tanzania into Kenya’s Maasai Mara, in search of fresh grazing and water. There is no single place or date to see it: the migration is a continuous cycle, shaped by the rains and different every year.
As new grass follows the rain and then dries out, the herds shift between the southern plains, the western corridors and the north. River crossings happen along the way, but they are natural events — no one can say when, or whether, a crossing will take place on a given day.