Picture this: Narrow undersea passages encrusted with bristling -- and stinging -- life. A crimson waterborne haze of toxic gas. A tide-driven vortex capable of siphoning a hapless diver to oblivion.
Actually, you don't have to picture it. As with the Vietnam expedition and an earlier tour of Mexico's Cave of Crystals, National Geographic has done it for you in another series of breathtaking photos.
The "blue holes" of the Bahamas are little-studied flooded caves containing some of the richest and rarest scientific treasure troves on the planet -- and some of the most dangerous, often requiring deep and highly delicate dives under tremendous time pressure. But the findings of blue-hole dives can have widespread implications in fields as far-flung as geology, archaeology, paleontology and biology. They could even offer insights for astrobiologists who postulate extraterrestrial life.
A team funded by the National Geographic Society with the National Museum of the Bahamas set out to explore the blue holes not long ago, and the magazine published the photos in its August issue.
Among the specimens the team found: a "living fossil" called a remipede, virtually unchanged for 300 million years; drifts of red sand blown in by ancient storms from the Sahara; and even human remains.
(Photo: National Geographic)