On the way to my daughter's near the Twin Cities is this octagon barn, but you can only see the roof from the road. I've known about it for years, but never had the nerve to drive up the driveway. The last time I went to my daughter's I noticed that there was no mail box at the driveway. So on the way home, I got up enough nerve to drive in, snap a couple of pictures, and leave.
To my surprise, there was a little octagon shed as well.