Albino Crayfish, Sims Sink, Florida, 1999

A blind, albino crayfish swims through the inky depths of Sims Sink in northern Florida. These colorless crustaceans are among the few creatures that have adapted to the lightless world at the bottom of the region's aquifers, springs, and sinkholes. Many species who make their homes in these freshwater labyrinths are endemic to only a handful of aquifers and are found nowhere else in the world.

(Text adapted from and photo shot on assignment for, but not published in, "Unlocking the Labyrinth of North Florida Springs," March 1999, National Geographic magazine)