National Geographic : 1970 Sep
VUAULUK turrIiK) T .VKlrtJ. BYCInJAMIBiE rn ni..rUmS n onlln l To the cellars of the sea THEIR BOAT double-anchored against currents from a hole off Rat Cay (above), the team dives during calm periods when the flow changes direction. A spelunker on land before entering his first blue hole, the author (lowering lights, left) has spent more than a decade explor ing these underwater labyrinths. Diving with scuba gear (right), he rigs a line to guide explorers returning from passages clouded by silt. His son George Jr. handles lights powered by separate systems in case one fails. On the boat, diver Archie Forfar prepares to follow, as a partly submerged camera cap tures both realms. 350 CHROMEBY BATESLITTLEHALES@ N.G .S.