Sir David Attenborough explores the seas on Earth to reveal a spectacular variety of life, from alien monsters of the deep, to pack-hunting killer whales attacking a grey whale calf.

David Attenborough journeys into the abyss to reveal the strange creatures that live in the depths of the ocean, from terrifying fish with massive teeth that eat prey twice their size, to weird jellyfish that flash in the darkness.

David Attenborough reveals the predatory skills of some of the most charismatic hunters found on the planet, such as whales, dolphins, tuna, shark, and rapier-nosed billfish.

David Attenborough reveals the survival techniques of creatures living on the frozen seas, such as polar bears in the Arctic and penguins in Antartica.

David Attenborough explores changes in the richest waters on Earth, where the annual cycle of the sun drives an explosion of life.

David Attenborough examines the fragile ecosystems of coral reefs, from the humble beginnings of tiny larvae to reefs hundreds of years old.