Growing up I had tropical (fresh-water) fishtanks. When I got older, I graduated to marine (salt water) tanks. I was, and am, facinated by the creatures that live there, especially "reef" tanks that house the stranger life forms like invertebrates and corals. I eventually took up diving, mostly because it was the only way I could be "inside" my tanks.
"The Deep" is an astonishingly GORGEOUS compilation of the most incredible, other-worldly creatures that inhabit the oceans. THIS is what thrilled me, and still does, about underwater life: it is the closest you will ever get to being on an entirely different planet!