More than anywhere, the Serengeti is synonymous with wilderness and has even come to represent Africa. But the story of the Serengeti is just as much about humans as it is about wildlife.

As the world's first national park, Yellowstone has long served as a model for the protection of wilderness around the world. For Americans it has become a source of great national pride, not least because it encapsulates all our popular notions of what a wilderness should be - vast, uninhabited, with spectacular scenery and teeming with wildlife.

The Amazon rainforest is the epitome of a last great wilderness under threat from modern man. It has become an international cause celebre for environmentalists as powerful agricultural and industrial interests bent on felling trees encroach ever deeper into virgin forest. But the latest evidence suggests that the Amazon is not what it seems.