Takes you on a twisting journey down the great rivers of the world, pausing to visit the thriving realm of freshwater ponds. Travel upstream to find civilization's source - then down again to see the key to our very survival.

Bodies of water surrounded by land on all sides are called lakes if they're large and ponds if they're small. Where does all that water come from? Bill Nye ponders this and many other freshwater questions in this exciting program.