The PBS television series Nature recently explored the "mystery shrouding fascinating -- and often fearsome -- creatures" in "The Secret World of Sharks and Rays." This companion Web site offers a number of online features, including feature articles on recreational shark diving, shark and ray diversity, and more. The site also provides a video preview of the program, featuring a segment on the characteristics of sharks and rays that set them apart from other fish. Interesting and informative (but not overly detailed), this Web site is worth a look for any audience.