A new pollution problem has surfaced in Guanabara Bay, the venue for sailing in the Rio de Janeiro Olympics. Sailors complained Monday about an oil slick that turned white boats brown with crews in town practicing for the Olympics, which open in a month. "We've never seen anything like this. It was all over the place," said Finnish sailor Camilla Cedercreutz. "There was no way you could avoid it." It's yet another in a long list of problems confronting South America's first games: the Zika virus, rising crime and violence, budget cuts, and slow ticket sales.