In the memorable second instalment of Blue Planet II, we are offered glimpses of an unfamiliar world – the deep ocean. The episode places an unusual emphasis on its own construction: glimpses of the deep sea and its inhabitants are interspersed with shots of the technology – a manned submersible – that brought us these astonishing images. It is very unusual and extremely challenging, we are given to understand, for a human to enter and interact with this unfamiliar world.