If snorkeling seems like something you can only do on a tropical vacation, think again. In this podcast episode, we meet a river snorkeling guide who encourages us to stick our heads in the water, right in our local streams and rivers. Keith Williams thinks you'll be amazed at the aquatic life you'll see there. Tune in to Constant Wonder and get hooked with some amazing fish tales. Guest: Keith Williams, author of "Snorkeling Rivers and Streams: An Aquatic Guide to Underwater Discovery and Adventure" and guide at Freshwater Journeys