More people have walked on the moon than have travelled to the very depths of the deep ocean. David Attenborough journeys into the abyss to show us, for the very first time, strange creatures straight out of the film Alien, many of which are new to science. Terrifying fish with massive teeth that eat prey twice their size and weird jellyfish that flash in the darkness. And deep sea sharks never filmed before and submerged mountain ranges and volcanoes far larger than anything on land.