Even if you're not sure if you'll need it, you should open a RiverLink account if you plan a trip to Louisville. You could be avoiding hassles down the road.
It used to be known as being the only bridge on Route 66 that featured a curve. Now, this Missouri bridge known as Devil's Curve has been left behind by time although life continues to cross it to this day.
If you don't mind being a little daring, there's a hike you can do in Illinois that will take you across one of the most scenic structures in the state. It's a 90 foot stone bridge and there are no railings to hold onto.