The Margins of the Land

David Attenborough examines the borders between land and water, and the life that thrives there - from the sticky mud of an English estuary and its bird and insect life to the more numerous life in the tropical mangrove forests.

He looks at the fish that hunt out of water, the world's largest reptile, the turtles that come ashore to breed in Costa Rica and the seven-foot-long leatherback turtle that can be found in Malaysia.