The St. Croix River has been in the news a lot of late, owing to the controversy over the new bridge that will link Highway 36 in Minnesota to Highway 64 in Wisconsin.
But this summer, the river becomes something else: A living biology lab and history lesson at the hands of Bob Downs, a seasonal National Park Service guide.
Downs leads free hour-and-a-half trips on the river every Wednesday evening from the Boomsite landing in Stillwater, holding forth on everything from heron rookeries to ancient pictographs.
Click on the audio link above to hear Downs on the latest episode of Minnesota Sounds and Voices. Then visit the National Park Service to make your reservation on the tour.