To me, songs are kind of like bookmarks. Have you ever listened to a song that you haven’t heard in a while, and all of a sudden, all the memories of that time period come back, and you remember what your life used to be like. They’re like milestones in your life.
And so on. No fear of running out of topics: there is more than one a day! I am sure my commenters can come up with tons more, probably some big ones that are not coming to mind at the moment (I did not list slavery, the abolitionist movement, the civil war, Reconstruction or Lincoln since they are, in fact, covered in history class, however poorly).