Walter Cronkite reviews the history of Yellowstone National Park, discusses the microbe that led to the Polymerase Chain Reaction technique used for fingerprinting DNA, and parallels Costa Rica to Yellowstoneâs hot springs as areas of important, but still largely unexplored, biodiversity. The video podcast of Yellowstone Revealed is presented by the American Society for Microbiology (www.asm.org) and the World Foundation for Environment and Development (www.wfed.org).