Divine Comedy, by Dante

Another classic I missed in High School. I was surprised by two things: 1) the amount of political commentary throughout, particularly in Inferno and Purgatorio, and 2) how pastoral and encouraging this work was overall. It was very difficult to follow from the audiobook (although the reader did a great job), and I probably missed 75% of the nuances, but in the end I was glad I slugged through it.