There is little doubt that the world would be a poorer place without the BBC's natural science documentaries, as it would without the well-modulated passions of David Attenborough.
And, while the two have often united to produce some of the best telly we're likely to see, they've rarely pulled off anything as impressive as The Blue Planet, which screened on the ABC last year and is now available on DVD.
Its eight 50-minute episodes offer an, ah, in-depth look at the masses of water that cover 71 per cent of our planet's surface and the creatures that inhabit them.
As some 97 per cent of this water is in the world's four oceans and seven major seas, that's where the BBC's cameras went. And the results are spectacular. Heaving waves, plunging bathyspheres, blue whales caught soaring out of the water in slow motion are among the visual highlights.
But there's much more than that, of course. Each episode investigates a particular aspect of life in the deep, after the first episode has laid out the broad facts and figures, identified the major currents, patterns of migration and types and availability of major nutrients, we're off, first into The Deep, then The Open Ocean, Frozen Seas, Seasonal Seas, Coral Seas, Tidal Seas, and the Coasts.
The Deep is indicative of the sorts of wonders that stud this astonishing series. We begin by following a shallow-water dweller as it plunges beneath the waves looking for food. Before long, David tells us, the water temperature plummets and the pressure soars. But it's the darkness, the complete absence of light, that is the most remarkable difference.
Sensory antennae take different shapes down here, and because of the sparsity of food, body shapes begin to change.
We see a gulper eel swim by, its cavernous mouth yawning alarmingly. Fish with headlamps casting beams of coloured light appear - and techniques of hunting and defence are explained. More people have stood on the Moon, we are told, than have visited the ocean floor.
This is vintage stuff that holds firm to the BBC's ancient precepts of educating, informing and entertaining. Miss it at your peril.
