Brazil's president signed a law on Friday establishing a truth commission to investigate human rights abuses by the military regime that ruled Latin America's biggest country from 1964 to 1985.
President Dilma Rousseff will appoint the seven members of the commission, which will have two years to complete a report.
The board will have subpoena power, can demand any document it wants from the government and can put witnesses under oath. But its recommendations won't result in any prosecutions as long as the country's 1979 amnesty law remains intact.
Unlike Argentina, Chile and Uruguay, which also had repressive military regimes, Brazil has never punished military officials accused of human rights abuses.
Rousseff also signed the "information access law" giving Brazilians the right to obtain information from federal, state and municipal government agencies.
The law establishes a 50-year limit on the amount of time documents considered "ultra secret" can be kept locked up.
"These two laws commemorate transparency and celebrate truth," Rousseff said at the signing ceremony. "They represent a decisive step toward the consolidation of Brazil's democracy."
Rousseff is a former guerrilla who was arrested and tortured in prison during the dictatorship.
The armed forces backed the commission after being assured that it would investigate abuses committed by rebels as well as by the military. They were also assured that the amnesty law that released civilians and the military from liability for politically motivated crimes will remain unaltered.
A recent study by the Brazilian government said 475 people were killed or "disappeared" by agents of the military regime.
"The youth and future generations must know the truth of our recent past when many people were arrested, tortured and killed," Rousseff said. "The truth about our past must be known so that acts like these that stained our history are never again repeated."
Besides Rousseff, several leading figures in Brazil were imprisoned, tortured or exiled.
Former President Luiz Inacio Lula da Silva was briefly imprisoned for standing up to the government as a union leader, and his predecessor, Fernando Henrique Cardoso, went into exile, as did singer Gilberto Gil, who later became culture minister.