Of vexillological note are the circus advertisement flags flailing in the background. They are long streamers with swallow tail ends. The body is mostly an eye catching yellow with a red border. The flags also announce the name of the circus.
The grand coincidence is that Indiana Jones movies are much like the modern day circuses that came to town every few years. It was a great show, but in many cases the modern day action spectacular movie has become nothing more than big stunt show.
But the difference with Indiana Jones is that a little bit of educational dressing is thrown into the mix so it doesn't just necessarily feel like a monster truck rally. It mixes history with legend into an exciting and memorable story.