I learned about the Anker clock when I was reading about Vienna before our trip. This large clock forms a bridge between two parts of the Anker Insurance Company building. A historical figure (or pair of historical figures) represents each hour. At 12:00, all of the historical figures move across the face of the clock.
I thought this sounded interesting, but didn't really want to plan a day around clock-watching. However, Scott and I each had some administrative tasks to tend to on Sunday. By the time we were done, it was pretty close to noon, and our hotel isn't far from the clock, so we decided to go. A crowd of maybe twenty or so people were gathered to watch.
I haven't found an exhaustive list of all the historical figures on the clock, although I also haven't researched it too exhaustively yet. It can be fun to guess or to make things up, anyway. I managed to get a photo of each historical figure or pair.