Interesting day. It's the feast of Our Lady of the Rosary, which seems at first glance to be a devotion of Italian origin centered on some healing miracles, and placed roughly opposite in the calendar to the rosary feast instituted after Lepanto. But there's a much older feast as well, one that I encountered when looking at some of the history in this part of the world -- the apparition of St. Michael the Archangel on the mountaintop. The pilgrimage to the mountaintop on this day was apparently a very important event at points in the medieval calendar. (Though if memory serves, one of the local observances moved it to the day before.)
The angelic cults and feasts are generally of eastern origin, and very broadly speaking, the Marian and rosary devotions are closer to the developed, established hierarchy of the Latin church. And, of course, Leo XIII is closely associated with St. Michael, with the prayer after Mass very popular in certain areas of the American Midwest (and occasionally sneaking into the Mass itself, before the dismissal). He was also a bit wary of Kantianism and Americanism, so I might have had difficult time making light talk, if I had found myself alongside the sede gestoria in the late 19th c.
Beyond doubt, one of the historic events of the age. The American mind will apparently have to sort through a few things in the coming years. The shining city on the hill might yet prove the litmus, one way or another. So those of us with some acquaintance with it have some thinking, reading and writing to do. Even if no one's listening quite yet.