New Orleans is the bedrock of American music. It's where jazz was born and R&B from the Crescent City laid the blueprint for rock n' roll. New Orleans is unique in America, not only for its music but also its food, architecture and communal ceremonies. But this roots culture is now endangered. The same underclass that suffered disproportionately from Hurricane Katrina also gave birth to this national heritage. Tangents takes an indepth look at America's foremost cultural treasure including music from Dr. John, Mahalia Jackson, Aaron Neville, Professor Longhair and many more.