one of the most important advancements in the recent development of rio de janeiro is the creation and deployment of the 'unidade de polícia pacificadora - upp (pacifying police) - a military-like police/peace force aimed specifically at restoring order in rio's favelas.

this special unit was designed and trained to be stationed inside rio's favelas permanently, to implement proper law enforcement and to help improve living conditions both inside and around these challenging districts.

historically, the majority of rio's favelas was under the rule of drug gangs, and occasionally militia groups. these groups controlled and limited access of law enforcement officers to their territories and jeopardized the safety of local residents by constantly engaging in armed battles with rival groups and with the police.