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In 1925 the geological connection between Flint Ridge and Mammoth Cave was proved when dye placed in a Flint Ridge spring showed up in Echo River at Mammoth Cave.

That tantalizing swirl of dye confirmed specula­tions that wereto tempt more than 650cavers over half a century with the thrill of being the first to make human passage of the cave connection. Roger Brucker and Richard Watson tell not only of their own twenty-year effort to complete the link but the stories of many others who w...