The Hawaiian coral reefs you know-the brilliant blue waters and rainbow fishes and the occasional sea turtle-are just a facade. Sorry, but it's true: Science says so. Dive past these upper-ocean paradises, deeper and deeper, and you'll find even more incredible reefs-ones that, shrouded in near-total darkness, shouldn't exist at all. Hundreds of feet below the ocean's surface, the so-called deep reef-also known as the twilight zone-is just coming into view.