The city successfully has hosted plenty of big events, from the 2014 World Cup to the annual Carnaval, which attracts as many as 2 million celebrators per day. But visitors are understandably unsettled by reports of gang violence in the city, of visiting athletes robbed at gunpoint and of security forces so underfunded that they can't combat the problems. During a protest at the city's airport, police and firefighters held up signs that read “Welcome to Hell,” suggesting they're ill-equipped to protect tourists arriving for the Olympics. Though security forces will be reinforced by federal troops and most Olympic events will be held well away from the most dangerous sections of the city, athletes from various countries have called for a greater focus on public safety in Rio. In response, the Brazilian government pumped an extra $26 million into its security budget for the games. The worries about safety have heightened because of wider political and economic instability. The state of Rio de Janeiro is broke, and Brazilian President Dilma Rousseff is suspended as she awaits a trial that could remove her from office. There are also environmental concerns, most notably pollution in the waters where sailing, canoeing and open-water swimming will take place. Rio officials say they've made progress on cleanup efforts but acknowledge they will not reach their goal of treating 80 percent of the sewage that flows into Guanabara Bay. Add to that the layer of concern over international terrorism that has accompanied every recent Olympics, and you get an unusually tense outlook. (Buda Mendes / Getty Images)
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