The longest-running documentary series in cable television history, honored with nearly 60 Emmys and hundreds of other awards, is celebrating a quarter-century on the air. Hosted by NGC correspondent Lisa Ling, Explorer: 25 Years provides an overview of how the series has covered our changing world, including the first look at the wreckage of the legendary Titanic and the rediscovery of the Afghan woman whose green eyes captivated the world from the cover of National Geographic magazine.