There is no more mysterious habitat on our planet than the deep sea! Researchers are just beginning to uncover more about it. What they discover down there is fantastic: monster-like fish with huge mouths and sharp teeth, jellyfish that can glow, and octopuses with ears. In some places, hot material shoots up from the ocean floor, forming the basis for life such as giant worms. So come along on an exciting journey into an unknown world! From the content: eternal darkness and high pressure: an extreme habitat, eating and being eaten: unusual strategies, about eggs and young: how deep-sea creatures reproduce, in the realm of black smokers, in the cabinet of curiosities of the deep sea, curiosity about the depths: on the exploration of the deep sea, endangered world: what you can do to protect the deep sea.