Some cities such as New York and London are famous for their subway systems. However, Cincinnati is infamous for its incomplete subway. It is currently the largest abandoned subway in America. Explore it and its history!
The popularity and affordability of the automobile are what what doomed Cincinnati's subway, not just the depression. I've been a tour docent there before. And Wikipedia's script has some errors.
Yet Cincinnati still makes millions on the lease of Cincinnati Southern RR to NS for over one hundred years. This money could have been used for the subway. Instead they have used it for airport terminal buildings now torn down at the Kentucky Airport! And interstate highway projects not the terminal there's no money for rail. Or even doing the new light rail line right. That would be finishing it go places people want to go.