Refers to the areas where you have underwater cliffs or walls. Or it could be located far from shore and in the "Bluewater" sits a coral formation which as a diver you drop down onto, to explore. The underwater cliffs, walls or formations could start on or near the surface and drop down further than the eye can see. These areas tend to have currents which means that you normally have large fans jutting out or corals that sway in the current picking up nutrients. Not only do corals like the locations Large Pelagic Fish will be common in these areas coming up from the depths. Thresher Sharks in the Philippines, Whalesharks in the Galapogas are some of the possibilities.