"All the construction work is on schedule," Rio Mayor Eduardo Paes told journalists in a nearly finished arena inside the giant Olympic Park building site. "With 12 months left to complete the challenge, it's liken "the end of a marathon," he said.

On August 5, 2016, the Olympic torch will end its own marathon - being flown around the world and carried by 12,000 people through Brazil - when it lights the flame inside the Maracana stadium for the opening ceremony.

Carlos Nuzman, president of the Rio Olympic organizing committee, reeled off figures illustrating the scope of the world's biggest sporting event - and of Rio's commitment.There will be 206 countries represented - the newest being recently recognized South Sudan - and 10,500 athletes competing in 42 sports over 17 days. Right after, the Paralympics will see 4,350 athletes from 176 countries in 23 sports.

To face the onslaught, Rio is assembling the equivalent of eight football fields of sporting gear - "a million items," Nuzman said - and 45,000 volunteer workers, with 25,000 on call for the Paralympics.

President Dilma Rousseff was to attend one-year ceremonies in Rio later Wednesday, along with the head of the International Olympic Committee, Thomas Bach. Bach, however, unexpectedly skipped the major press conference. Paes said that the IOC boss was worn out after flying from Malaysia -- and had also been enjoying Brazil's notoriously powerful national cocktail.

"Thirty hours of flying and then one Brazilian caipirinha makes people tired," Paes quipped. "It was just one caipirinha," he quickly added.

These will be the first Olympics held in South America and a chance for Brazil, the world's seventh largest economy, to look beyond a growing domestic brew of corruption and economic trouble.Already the Olympic Park is 82 percent ready and Olympic Village 89 percent complete, Paes said.

But the generally positive picture darkens in what environmentalists and Rio residents describe as the horrific pollution in Guanabara Bay, where sailing and windsurfing contests will take place. Environment experts say most of the sewage produced by the 12 million people in greater Rio goes untreated directly into the bay. In addition, dozens of rivers leading to the bay are filled with garbage.

In its original bid to host the Games, one of Rio's promises was to reduce that pollution by 80 percent -- a goal that no one now even pretends can be met. Officials are on the defensive and on Wednesday they once more insisted that there was no danger to athletes' health or to their boats.

Latest News from Sports News Desk