I think that's that. I'll put this painting away for a couple days and then look at it with fresh eyes to see if I'm missing anything. This has been a fun and challenging project, but I'm ready to get back to painting Portugal, and I have some portraits in mind that I need to get started on.
Update - Now it's done. The bridge suffered from a lack of definition, especially in comparison to the objects behind it, so I sharpened some of the details and deepened some of the shadows to define it better. Thanks Ran, for the suggestions.