Another wonderful story from the World of Science:

Ocean explorer Robert Ballard takes us on a mindbending trip to hidden worlds underwater, where he and other researchers are finding unexpected life, resources, even new mountains.

I am very ignorant of what’s out there in the deep blue briny, but I do know of two wonderful sources of information in this regard; Redmond O’ Hanlon’s Trawler and Bill Bryson’s A Short History of Nearly Everything (get the illustrated version – it’s well worth the extra expense).