Luckily Kenya is setup to experience this phenomena. There is easy access from Nairobi, a six hour drive or less than two hour flight
The best time to go is between July and October, this gives a great opportunity to see crossings over the river.
One of the wildlife wonders of the world the great migration across the Serengeti and Masai Mara is something to behold. Thousands upon thousands of game fill the lands and give many perfect opportunities for great shots.