We move swiftly forward in three rows of two, each officer training his weapon in a different direction to reduce our vulnerability to surprise attacks. The two point men lead with .40 caliber submachine guns, while another protects the rear with the same. The others hold tightly to their pistols with both hands, index fingers feathering their triggers. We are silent, communicating only through hand signals and the occasional whisper. We halt at every intersection in the gian

Understanding the origins and persistence of urban slums in Brazil.