"Cracolandia" - that is the name given to the dark streets ruled by crack-cocaine addicts in the centre of the Brazilian city of Sao Paulo.
They congregate by the hundreds and are tolerated by police because they keep out of sight.
But recent plans for the re-development of the area have forced the users and drug-pushers out of the shadows and into neighbouring streets.
It is a problem the authorities have so far refused to deal with. Gabriel Elizondo reports.