Earth's oceans / Blue planet -- The oceans -- Oceans apart -- Salty seas -- The water cycle -- Ancient oceans -- The ocean floor -- Incredible islands -- Waves -- Currents -- Tides -- Coastal erosion -- Danger zone -- Meet the animals / Small wonders -- Spectacular sponges -- Jazzy jellies -- Shining stars -- Spectacular shells -- Snappy crabs -- Brilliant bivalves -- Super squid -- Enormous octopus -- Sea snails and slugs -- Marine reptiles -- Terrific turtles -- Fishy friends -- Fabulous fish -- Superb seahorses -- Leafy sea dragons -- Sleek sharks -- Rays and skates -- Diving dolphins -- Wonderful whales -- Big blue whale -- Unicorn of the sea -- Walruses, seals, and sea lions -- Playful penguins -- Soaring seabirds -- Ocean environments / Seashores -- Coastal habitats -- Mangroves -- Seagrass meadows -- Kelp forests -- Coral reefs -- Coral-reef life -- Natural reefs -- Artificial reefs -- Icy waters -- Arctic waters -- Antarctic waters -- In the zone -- Sunlight zone -- Twilight zone -- Midnight zone -- Abyssal zone -- Living in the ocean / Family matters -- Turtle power -- Riding the waves -- Swimming together -- Perfect partners -- Ocean wanderers -- Whale adventure -- Arctic food web -- Amazing algae -- Marine hunters -- Self defense -- Masters of disguise -- Natural glow -- Ocean of sounds -- Super sonar -- Smart sea creatures -- Ocean adventures / Early exploration -- Silk road of the sea - Ocean exploration -- Science at sea -- Ships ahoy! -- Searching for shipwrecks -- Terrors of the sea -- Myths and legends -- Exploring machines -- Ocean equipment -- Mapping the ocean -- Deep discoveries -- Exploring the Mariana Trench -- Underwater mountains -- Inside a sinkhole -- Ocean heroes -- Sports records -- Ocean and us / Fun at sea -- Beach vacations -- Living underwater -- Work on the waves -- Ocean rescue -- Sea supplies - Fishy business -- Ocean hazards -- Climate change -- Plastic problems -- Saving our seas -- Journey into the unknown.