Brazil has deployed federal troops to Rio de Janeiro in an effort to rid slums of violent crime, drug traffickers, and gangs ahead of the FIFA World Cup in June.
The drug lords are fighting back against the authorities, trying to recapture their territory after years of police occupations.
This violent battle has raised concerns about safety and security at the upcoming World Cup soccer tournament in Brazil, which hundreds of thousands of foreigners are expected to attend.
The final game in the tournament will take place at the Maracaná stadium, a few miles from the Manguinhos slums.
Rio de Janeiro is also hosting the Olympics in 2016.
Thousands of policemen in Rio patrol the slums where 1.5 million people live. The Metro Mangueira slum (on the right) will be demolished for construction of World Cup infrastructure.
Thousands of families will be displaced to make way for sports and tourism facilities. In this photo, Maracana stadium is seen between two favelas, or slums.
Violence pervades the slums -- daily shootouts have become the norm as drug traffickers fight for control of the neighborhoods.
Drug lords are using residents' discontent with police as an opportunity to reconquer their lost territory.
Imprisoned drug gang leaders have ordered attacks on police in order to disrupt their operations in the slums.
Some residents are wary of the police. Corrupt officers have been accused of human rights abuses and torture in the slums.
Some people in Rio say they'd rather live under the control of the gangs than the police, even with drugs flooding the favelas.
The drug problem in these slums had gotten so bad last year that drugs were sold in open-air markets with no fear of police intervention. Some kids get addicted to cocaine and crack.
Many of the drug traffickers are armed -- police forces conduct searches for weapons in the slums to try to eliminate the guns.
Despite the efforts of the police forces, Rio is still dangerous. The State Department has rated the city as 'critical' for crime for the past 25 years.
Thousands of additional police officers have been hired to help bring the slums under control by the time the Olympics begin in 2016.
Police will become a permanent presence in some slums that drug traffickers have controlled for decades.
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