A preview from The Deep Sea, ep11 of the BBC’s Nature’s Microworlds: 

Steve Backshall takes us to a place few have ever visited - the deep sea. 99 per cent of the space on Earth inhabited by life is under the ocean and almost 90 per cent of this is deeper than a kilometre, a place of perpetual darkness and crushing pressure. Far from being lifeless, the vast inner space of our planet contains an extraordinary array of beautiful and bizarre creatures, from 40m-long jellyfish to grotesque angler fish and vampire squid. Our journey from the sunlit surface waters to the deepest reaches of the abyss reveals how life persists in such a hostile world.