An estimated crowd of nearly 250,000 people attended the obama rally.
And the whole world saw Chicago in a very favorable light because no serious problems were reported before - during or after the big event.
The weather was fabulous, and that can't be minimized. The crowds were in a festive mood. The city says there was not a single arrest in the mass of humanity at grant park. The whole world was watching, and it saw history made in a remarkable show. For the city, there will be many dividends from this election day, and one of them should play well with the city's Olympic bid.
Everywhere in and around Grant Park Tuesday night, there was celebration. Tens of thousands of people came to watch and listen and share in a moment.
"The demographics say we're moving more toward a united melting pot and this is a perfect example of what's happening," said Evan Kokinos, Chicago.
Different colors, different ages, shared excitement.
"This shows we can go beyond the color of our skin to make some real changes for everyone," said Etta Moore, Austin, Texas.
For many last night, the emotion was overpowering.
"We're not looking at one man. We're looking at a nation on that stage, and he's representing a lot of people and a lot of change," said Danielle Hill, Chicago.
The mayor on Tuesday likened all the excitement to a homecoming celebration. And the reality that there were no arrests, no serious incidents amidst a massive celebration was an image good as gold for a city that wants to host the Olympics in eight years and now seeks that crown as the home to a new president.
"Your prime minister, your president has to carry the ball. You have to have that," said Mayor Richard Daley.
Barack Obama has been very engaged in Chicago's Olympic bid, and now will be asked as president to appear before the International Olympic Committee next year before it selects the host city. The head of the Chicago 2016 committee doesn't want to overplay the President Obama factor but knows the diversity Obama has inspired will be very positive to an Olympic bid.
"Last night we could see tremendous diversity, I've never seen anybody do it," said Pat Ryan, Chicago 2016 Committee.
Former British Prime Minister Tony Blair and ex-Russian president Vladimer Putin both made strong - in person pitches before the IOC. London's got the 2012 Games. And the 2014 Winter Olympic Games are going to Russia. Having an athletic-minded president pitching Chicago should be hugely significant.