For us, barrios are by dictionary definition any neighborhoods, basically. In Venezuela, like favelas, they are also mostly built mountainside (cerros), and I expect most Forumosans will be most familiarized with favelas as a term than barrios/tugurios/ranchos/zona marginal, etc. so I mostly use that term instead of slums so they will have the mental picture. We have topical names aplenty depending on the country.
I guess that when you’ve lived enough revoluciones like this old hag, well, it’s experience and memories rather than dreams and hopes. One wished there was a way out instead of repeating the same historical mistakes over and over and over again.