Dream of Africa and chances are that you dream of the Masai Mara. This huge expanse of gently rolling grassland – speckled with flat-topped acacia trees and trampled by massive herds of zebras and wildebeest – is the ultimate African cliché. But for once the reality lives up to the image and the Masai Mara is for many people not just the highlight of their Kenyan adventure but the very reason they came in the first place.