I must remember, next time I'm on the dance floor, that I'm dancing Flamenco. It's easy to overlook.
All dance forms have some root in folk dance, but most are so far removed from them, that the reference is irrelevant. Tango is certainly one: and in anything like its modern form (last 120 years, at least) it is uniquely (among other forms) an URBAN dance. The myth that gauchos danced it is widespread, but almost wholly wrong. They danced other folk-derived forms, including, of course, milonga - the original and authentic milonga, that has really very litle to do with the dance of that form we enjoy today.