Rio de Janeiro–São Paulo megalopolis

The Rio de Janeiro–São Paulo Megalopolis, also known as the Brazilian Megalopolis and the Southeast Brazilian Megalopolis, is a megalopolis in Southern Brazil consisting of the cities of Rio de Janeiro and São Paulo, as well as their surrounding urban areas. Their process of conurbation is occurring between the Expanded Metropolitan Complex, in the state of São Paulo, and the Rio de Janeiro metropolitan area.

Source: Wikipedia — Rio de Janeiro–São Paulo megalopolis (CC BY-SA 4.0)