Well, enough musicology lectures, but we'll stay in Tower Grove Park. I couldn't figure out what these chalk markings on the bike and running path were for. There must have been some kind of event but no sign of what. It's hard to read the word at the top of the first picture but it says "walk." Then the one below says "run." Maybe it was some kind of psychological test to see how people respond to conflicting orders.
No swimming allowed on Downtown St. Louis 365.