A million wildebees... 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 40km (25 mile) long columns plunge through crocodile-infested waters on the annual exodus north; replenishing the species in a brief population explosion that produces more than 8,000 calves daily before the 1,000 km (600 mile) pilgrimage begins again. Tanzania's oldest and most popular national park, also a world heritage site and recently proclaimed a 7th world wide wonder, the Serengeti is famed for its annual migration, when some six million hooves pound the open plains, as more than 200,000 zebra and 300,000 Thomson's gazelle join the wildebeest's trek for fresh grazing. Yet even when the migration is quiet, the Serengeti offers arguably the most scintillating game-viewing in Africa: great herds of buffalo, smaller groups of elephant and giraffe, and thousands upon thousands of eland, topi, kongoni, impala and Grant's gazelle.