Airs: 8:00pm - 8:50pm on BBC One
A place of mountain ranges, perpetual night, pressures extremes and cold... and the weirdest life forms on our planet. Dive into the depths of the ocean, an eerie world where predators with teeth so large they can't even close their mouths, chase bio-luminescent creatures of the deep. Discover the spectacular smoking chimneys of the hydrothermal vents. Go deeper down than you have ever been...