Saw a PBS special last night that was pretty incredible. I believe it was from 2003. Entitled "Water's Journey -- Hidden Rivers of Florida," and explores Florida's aquifer system. It was made by underwater filmmaker Wes Skiles and cave diver Jill Heinerth. Two divers and a cameraman were diving a section of Florida's underground aquifers, with two guys on the surface following their radio signal. The purpose was to map the aquifers and to check the condition of the water supply. Showed video of these two divers trying to squeeze thru what looked like 1 ft. spaces in these UW caves with all of their bottles strapped to them. At the end of the show they said the divers went a total of about 10 miles underwater. Now, I've never dove in a cave, and after that show it's pretty clear I never will, but it raised a whole bunch of questions. First of all, these "caves" snaked all over the place, and in places were so tight that they could barely fit thru. I can't imagine how they could enter a cave system where they didn't know if they could make it thru, or whether they could make it to an exit point. If there was one. Second, it sounded like they were diving very deep in places. I thought I heard them say 180 ft. at one point. Now at that depth, time is of the essence, and if you get stuck or slowed down, or have to go back to where you entered, you could be screwed. Third, they were talking about "hours of decompression". How can you plan your dive, including hours of decompression, in an unmapped cave. I have a bunch of other questions, but I think they all come down to this: either these aquifers and caves were previously well mapped and the dives were far better planned than the show implied, or these folks were insane. Anyone?? EDIT: I finally found a website (http://www.floridasprings.org/expedition/) that addresses the PBS special. Here is an answer to a question asked of the dive team: "Our divers used special "re-breather" systems, which enable them to "recycle" their air unlike traditional SCUBA equipment. This enables the divers to stay underwater for long periods of time and explore extreme depths; some divers can stay underwater for as long as 20 hours or more. During our Wakulla dive, it took about 45 minutes for Jill and Paul Heinerth to dive to about 300 feet and explore the caves. It then required nearly five hours of decompression time during which Paul and Jill had to very slowly make their way to the surface, stopping at different depths to ensure that they would not get the "bends."