A municipal agent (L) argues with a woman, who agents say is a suspected crack user, during an operation by Rio de Janeiro's Social Action Secretariat to bring crack addicts to shelters for rehabilitation, near Parque Uniao slum October 17, 2012. Municipal agents approached people showing signs of crack abuse during the operation to offer to send them to the shelters as part of efforts by authorities to end crack use in Rio's slums, including 11 areas known as Cracolandias or cracklands in the city. The exercise is mainly voluntary except for suspects that broke the law. REUTERS/Ricardo Moraes