I had no idea! I've run past a landmark two years in a row and not even noticed!
This year was different, however. The Cincinnati Flying Pig Marathon/Half Marathon decided to eat my lunch this year and I found myself walking along bits and pieces of the route where I'd normally be running.
As I came up onto a left-hand turn around mile 9 or 10, I noticed a fellow aiming a camera, not at us runners, but at a house up on a hill above us. Next to him was an historical marker and - since I was walking at the time - I had enough time to read the sign and to look up at what he was photographing.
It was the Harriet Beecher Stowe House. (link) Well of course I had to Google it!