David Attenborough narrates a tour of landscapes chosen for scale and strangeness, from the high, icy terrain of the Himalayas to Caribbean coastlines and the rainforests of South America. The film moves continent to continent, pausing in each place to look at the animals and plants that live nowhere else, among them mountain gorillas in Africa's forests and birds of paradise in their display grounds. Attenborough's narration supplies the natural history behind each location: how a given ecosystem formed, what keeps it running, and why its inhabitants evolved the way they did. The structure is straightforwardly geographic, one striking environment after another, with the animal and plant life treated as evidence of how varied the planet's habitats actually are. There is no single argument being built here, just a survey of extremes, mountain, jungle, coast, wilderness, held together by Attenborough's presence and the through-line of what makes each place ecologically distinct.