Far below the jeweled surface of the oceans, deeper than the sun's rays can dive, there are fantastical creatures unlike anything seen on land. Deep currents-cold, black, and full of mystery-are home to secretive fellows such as the anglerfish, which uses light as bait, and vampire squid, whose red eyes peer out from a cloak of spiny tentacles as it "flies" through the water. Down in these depths, whale bones become entire cities where palm worms...