Following the BAFTA-winning series Inside Nature's Giants, this one-off special film goes beneath the surface of the giant squid. Long thought by many to be the stuff of legend, it was only in the late 19th-century that the giant squid was first officially recorded by scientists, after one leviathan squid washed up on a beach in New Zealand. Related to slugs and snails, this monster from the deep, along with its cousin the colossal squid, is the largest invertebrate in the world.