In the opening of the series, David Attenborough narrates: "Our planet, the Earth, is, as far as we know, unique in the universe. It contains life. Even in its most barren stretches, there are animals." As the narration hints, he explores every corner of the planet. First, he goes to the world's deepest valley in the Himalayas where temperatures range from those of the tropics in its lower reaches to that of the poles higher up. This is an example to show how creatures become adapted to living in certain environments. And he explains how the Earth has become formed as today as well as examines the life around volcanic eruptions. Then he explores the polar regions, the northern coniferous forests, the jungles of the tropics, the savannahs of Africa, North America and South America, and the world of deserts. And then he looks at the creatures that spend most of their lives in the air, freshwater habitats and their inhabitants, coastal environments and the effects of tides, remote islands and their inhabitants, and the marine environment. Lastly, he tells of "New Worlds" that humans have changed so far not only by creating new ones like villages and cities but also by destroying environments like deforestations and oil spills.