Rio de Janeiro sure is pretty, but things can quickly turn ugly. Alemão is one of Rio’s most violent favelas, an interlocking collection of shantytowns in the midst of the city. Several years ago, members of the Red Command, the gang that runs Alemão, dismembered the body of a Brazilian journalist here, stuffed his carcass in a gas-filled drum, and lit it on fire. As the city prepares to host the World Cup and the Olympics, the authorities are cracking down. It took several branches of the army and police to pacify Alemão late last year. But this favela is largely beyond control. When I visited Alemão for an illegal, open-air party, I watched teenage gang members brazenly peddle a bonanza of hard drugs as they smoked crack, their eyes glazing over, automatic rifles dangling from their shoulders.