The producers of Life, Galapagos and Yellowstone bring US the Great Rift. Visible from space, Africa's Great Rift Valley runs four thousand miles from the Red Sea to the mouth of the Zambezi - a diverse landscape of erupting volcanoes, forest-clad mountains, spectacular valleys, rich grasslands, vast lakes and mighty rivers. Home to the greatest concentration of animals on earth - lions, crocodiles, elephants, hippos and flocks of flamingos - and pastoralists such as the Maasi - this is a land of constant geographical turmoil. It will take you to another world - a world of exotic extremes, where the forces of nature have shaped the landscape and so created a hotbed of evolution. It is the very cradle of mankind.