Ray Batchelor writes: The title I have given this image is taken from the “Tangology” website: http://www.tangology101.com/main.cfm/title/Tango-History-in-Pictures/id/1165
I find this image interesting because it shows women same sex couples in public. I expect the identification of the location according to Tangology is accurate, although I have seen the same image confidently identified as the Avenida de Mayo in Buenos Aires. Are they dancing tango? I don’t think we can really say, but it is notable that this image crops up on a great many contemporary  tango websites.