David Attenborough follows the river Amazon from the Andes to the sea. The life in and around it changes as it flows on its four-thousand mile journey from cold torrents to a vast warm delta. There are similarchanges in other rivers, producing such variety as torrent ducks, mayflies, hairy frogs, piranhas, giant otters, fishing owls and the Marsh Arabs of Iraq.

David Attenborough explores the isolated islands which are a haven for ancient species as well as the cradle of new ones.

Stepping into the past he sees the world's largest lizard, the komodo dragon, and in the Indian Ocean he visits an island where 150,000 giant tortoises find survival a pressing problem. In Hawaiian forests live a unique group of birds, the honeycreepers, and living among them, a caterpillar that catches flies.