Yes, I know there are versions of authoritarian socialism in South America that have been tried, but I want to know if there are any successful democratic socialist communities that lasted at least twenty years (since the US Census Bureau designates a generation based on the 20 year timespan of the Baby Boomer Generation) and were located in South America or Latin Amerca. The only communities close to these criteria I have found have not lasted very long like Argentinian Horizontalidad and Oaxaca City.
To make things clearer, I'm looking for a country or at least autonomous / semi-autonomous community that existed for 20 years in Latin America or South America that successfully practiced democratic socialism.