One of the more interesting interviews I've heard on NPR was a conversation with Robert Plant about the history of the blues. As I recall, he said he had an epiphany of sorts when he was in Morocco and, while listening to some street musicians (I forget in which city) heard chord structures and other musical "markers" that were (for him) the missing link between other African influences and Delta blues. This interview was quite a while ago, so I don't recall all the details. The other interesting thing, for me, was learning what a committed student of music and musical roots he still was.