Be careful what you wish for. Now that he's won the Olympics, Brazil's President Luiz Inácio Lula da Silva faces a truly unenviable task: ridding Rio de Janeiro of its violent crime before the world's athletes come calling in 2016. "The security problem is very serious," one Brazilian athletic official told Bloomberg News. There are stats to prove it: Home to 7 million people, Rio is one of the most violent cities in the world, recording 2,069 murders last year. According to the United Nations, the police are responsible for one in five of those killings.