Serengeti National Park.

A million wildebeest… each one driven by the same ancient rhythm, fulfilling its instinctive role in the inescapable cycle of life: a frenzied three-week bout of territorial conquests and mating; survival of the fittest as 40 km long columns plunge through crocodile-infested waters on the annual exodus north. This trek replenishes the species in a brief population explosion that produces more than 8,000 calves daily before the 1,000 km pilgrimage begins again.

Size: 14,763 sq km
Location:

335 km from Arusha, stretching north to Kenya and bordering Lake Victoria to the west.
Getting there: Scheduled and charter flights from Arusha, Lake Manyara  and Mwanza. Drive from Arusha, Lake Manyara, Tarangire or Ngorongoro Crater.
What to do:

Hot air balloon safaris, Maasai rock paintings and musical rocks. Visit neighboring  Ngorongoro Crater, Olduvai Gorge, Ol Doinyo Lengai volcano and Lake Natron’s flamingos.
When to go:

To follow the wildebeest migration, December-July. To see predators, June-October.
Accommodation:

Lodges/Luxury Tented Camps, basic camps scattered throughout the park. There are also lodges and luxury tented camps outside the park.