Rio de Janeiro is Brazil's most famous city and the second largest Brazilian metropolis after São Paulo. Historically, Rio de Janeiro was Brazil's political, cultural and financial capital and was lovingly called by its inhabitants 'a cidade marvilhosa', or the marvellous city, for its natural beauty. The proposed answer to Rio de Janeiro's security problem came in the form of the Pacifying Police Unit programme, Unidades de Policia Pacificadora (UPP). In the areas of urban development, housing, sanitation and infrastructure, both the state and municipal governments have outlined a series of policies seeking to improve favela communities. The city government, in coordination with the state and federal governments, communities, civil society and private sector, delivers this part of the process. In addition there exists the continued challenge of developing a solid basis for sustainable socio-economic development, closing the gap between those living in the now pacified favelas and the rest of the city.