The Great Wildebeest Migration is astonishing. Each year, more than 1.5 million wildebeest trek from the Serengeti to the Masai Mara and back again in search of fresh grazing. Their crossing of the Mara River is the climax of this odyssey, a spectacle filled with drama, death and endeavour and one of Kenya’s best safari experiences.

It was to be the most unforgettable day: an encounter with Africa’s Great Wildebeest Migration. The previous evening we’d sat on the terrace of our safari lodge and watched vast swathes of black moving across the plains. In the dusk, those first battalions of wildebeest had looked like locusts, pouring into the Masai Mara from the plains of the Serengeti.

We were up early, tense with excitement. Soon, our open safari vehicle was heading for the Mara River. ‘The wildebeest are building!’ said John, our guide, as we drove along the river’s steep embankments. I looked across the muddy waters to where animals were starting to mass. It was a sea of dark hides, curved horns and shaggy beards, the air filled with their loud honking.

Looking closer, I noticed that in among the wildebeest were the stripy shapes of zebras and groups of Thomson’s gazelles, joining their comrades on this mighty endeavour. In the distance, from every direction and stretching to the horizon, I saw lines of animals, many in single file, heading towards the river.

‘Each year, more than two million animals trek from Tanzania to Kenya and back again on a never-ending cycle to find water and grass,’ explained our guide. ‘The climax of Africa’s greatest theatre piece is the fording of the Mara River. And it looks like today we’ll be blessed with a crossing.’

The vehicle drew to a halt and we trained our binoculars and long lenses on the river. The animals were bunching along the banks, waiting for one of their numbers to take the plunge. Quivering bodies, indecision, terror. One brave animal stepped closer, sniffing the water. It looked right and left, dipped a hoof into the current. Suddenly, it leapt into the stream. More followed in a hail of splashing and noise.

Everywhere along the bank, wildebeest poured into the stream. The air was filled with dust and gnu-ing, like the sound of a hundred beehives. We watched the spectacle, dumbstruck. I’d never seen or felt anything quite like it … a mixture of elation, fear and awe.

The crossing had become a frenzy. Animals leapt from a high bank, some of them landing on the backs of others in a churning melee of bodies. A lone wildebeest was overwhelmed by the current and dragged towards a giant hippopotamus. The hippo lifted its head out of the water and opened its enormous mouth, baring its tusks. The wildebeest swung away frantically and made for the bank from whence it had come. My hands were shaking so much, I could hardly keep the camera steady.