Favelas are informal settlements that have grown around large cities in Brazil, often housing low-income residents or former slaves who have nowhere else to live. The first favela appeared in Rio de Janeiro in the late 19th century as settlements built by soldiers returning from war with no homes. Favelas range from having some security from pacifying police units to having little or no security and being controlled by drug dealers and militias. In preparation for a visit from the Pope, police raided the Rocinha favela in Rio de Janeiro, arresting 30 people and dismantling 100 drug stalls, as part of an operation to increase security.