Watch on Soap2day. It's one of the ocean's most extraordinary and mysterious creatures. It's often seen, but very little is known about it: it's the bluefin tuna. It's faster than a dolphin and its hunting prowess rivals that of a great white shark. Traveling at over fifty miles per hour, it crosses the oceans. However, very little is known about its movements and life history; it's a creature so evolved that it escapes human observation. National Geographic guides us on a journey to discover the bluefin tuna.