Discover the abundance of life underneath the surface.
How Earth's five oceans connect to form the largest ecosystem on the planet.
Exploring tropical paradises and storm-ravaged icy polar seas.
Michael starts a Pacific voyage in the Diomede Islands and visits Alaska and Russia.
How water plants create some of the most beautiful and bizarre spectacles in nature.
David Attenborough looks at some of the 30,000 species of fish.
