In a vote of high drama, the bustling Brazilian carnival city of beaches, mountains, and samba beat Madrid, which became a surprise finalist with a big helping hand from an influential patron - a former Olympics chief.

President Obama's last-minute hop to Denmark didn't swing the Games Chicago's way. He came, he saw, and he charmed, but he did not conquer. Chicago was knocked out in the first round - in one of the most shocking defeats ever handed down by the International Olympic Committee. Tokyo, which trailed throughout the tight race, did better, making it to the second round.

"You can play a great game and still not win," Obama said on his return to the White House.

On Rio's Copacabana beach, where the city will hold beach volleyball in 2016, the party went into the night. In Chicago, there was bewildered silence. In Washington, Obama aides tried to explain what went awry. Rio was a very strong candidate, they said.

"In this town, you'd be criticized if you didn't go, you'd be criticized if you did go," said senior adviser David Axelrod. No, he said, the setback would not be a drag on the health-care push or other presidential priorities.

Even with Rio's daunting reputation for crime, the city spoke to IOC members' consciences: Rio argued that it was simply unfair that South America has never hosted the Games, while Europe, Asia and North America have done so repeatedly.

"It is a time to address this imbalance," Brazil's charismatic president, Luiz Inacio Lula da Silva, told IOC members before they delivered their verdict. "It is time to light the Olympic cauldron in a tropical country."

The final result was decisive: Rio beat Madrid by 66 votes to 32. Chicago got just 18 votes in the first round, with Tokyo squeezing into the second round with 22. Madrid was leading after the first round with 28 votes, while Rio had 26.

In the second round, Tokyo was eliminated with just 20 votes. Madrid got 29, qualifying it for the face-off with Rio, which by then had a strong lead, with 46 votes.

In Chicago, where residents had gathered at Daley Plaza, an audible gasp went up from the crowd when Chicago's dismissal was announced.

Beating three rich, more developed nations that had all previously held the Games represented a giant, morale-boosting coup for Brazil, a nation bounding up the ranks of the world's biggest economies but which still has millions in poverty. Rio is known as much for its crime-ridden slums as for its natural beauty.

Lula, a bearded former union leader, disappeared into a huge group hug with the joyous Rio team after IOC president Jacques Rogge announced the city's name. Football great Pele had tears in his eyes.

Brazil will now hold the world's two biggest sporting events in the space of two years: In 2014, it will be host for the soccer World Cup.

The slap to Chicago left some IOC members squirming.

Chicago's plans for Olympic competition along its stunning Lake Michigan waterfront had made it a front-runner. Obama and his wife, Michelle, flew in before the vote to butter up IOC members, an essential part of the selection process.

IOC members had seemed wowed, posing for photos with the first lady and taking souvenir shots of the president. But, in the vote, Chicago was shunned.

"Either it was tactical voting, or a lot of people decided not to vote for Chicago whatever happened," IOC member Gerhard Heiberg of Norway said. "Nobody knows, but everybody is in a state of shock. Nobody believes it. I'm very sorry about it."

Rio's bid, while high on romance, is not without risk. Because of high crime and murder rates in the city of six million, security will be a constant issue in 2016. Preparing Rio for the Olympics will cost billions of dollars - money that critics said would be better spent on the city's social problems.

But the lure of the untapped frontier proved too strong for the IOC. "There was absolutely no flaw in the bid," said Rogge, a Belgian.

Now, Africa and Antarctica are the only continents never to have been awarded an Olympics.

Madrid's surprising success in reaching the final round came after former IOC president Juan Antonio Samaranch, a Spaniard, made an unusually personal appeal for the Spanish capital, reminding IOC members as he asked for their vote that, at 89, "I am very near the end of my time."

Senior Australian IOC member Kevan Gosper surmised that Asian voters may have banded together for Tokyo in the first round, at Chicago's expense, in "a stupid bloc vote."

He worried that the shock exit could do "untold damage" to the already-testy relations between the IOC and the U.S. Olympic Committee. They had recent flare-ups over revenue-sharing and a USOC TV network.

The IOC's last two experiences in the United States were bad: The 2002 Salt Lake City Winter Olympics were sullied by a bribery scandal, and logistical problems and a bombing hit the 1996 Games in Atlanta.

"He didn't do too much," French IOC member Guy Drut said of Obama's visit. Drut said that the USOC's financial disputes with the IOC were still unresolved. And he said White House security unnerved some IOC members.

"This morning the city was closed because of Barack Obama," Drut said.