Heliopolis is a district town in the district of Sacomã, in the southeast area of São Paulo, Brazil. Composed of fourteen plots, it has about 100,000 inhabitants in an area of almost one million square meters. This makes it the largest slum population in the city, but the second in area behind Paraisópolis. Once considered the largest favela in Brazil, through a process of urbanization Heliopolis today has the status of a neighbourhood. It began as a series of vacant lots and a few homes of factory workers, but from the 1960s and 1970s there was a large land invasion. The slum was built illegally, but was consolidating and turning into a neighborhood.
In the area housing estates were built and CDHU COHAB replaced degraded horizontal buildings, although there are still several tracts in this condition. The dirt roads were replaced by asphalt, and thus consolidated in structure. The neighborhood abuts the city of São Caetano do Sul and a stream, but due to the conurbation process these limits are not noticeable. On the banks of the creek there are electricity towers and undergrowth, representing the only green area on the border between São Paulo and São Caetano do Sul, since the other border is Tamanduateí River Blvd. This is a neighborhood of middle, lower middle and lower class populations. There are avenues of trees in some parks. In March 2008, international delegations visited the urbanization works in Heliopolis to study urban design and model the use of public space. Delegations were present from Lagos (Nigeria), La Paz (Bolivia), Cairo (Egypt), Manila (Philippines) and Ekurhuleni (South Africa).