Thousands of supporters gathered under blue skies in a downtown Chicago plaza with high hopes of winning the 2016 Summer Games at a vote by Olympic committee members later Friday.
Amanda Vargas, 17, cheered and waved a handmade sign as the countdown to the 1630 GMT vote began with a live band a series of videos extolling the Windy City's bid.
She came with a group of fellow students from her school on Chicago's South Side which is just blocks from many of the proposed sites.
"We want to win because it's going to help the city," Vargas said.
"It'll be a lot of new stuff developing and jobs will be provided for our class," added Nancy Torres, 17, who said her favorite Olympic sport is swimming.
Architectural interns John Svast and Jeff Perkins skipped work to join the rally in Daley Plaza, named after the current mayor's powerful and long-serving father.
"We're going to get the Olympics, I'm pretty convinced," said Svast, 29.
Asked what it'll mean for the city, Svast laughed: "build, build, build. Lots of jobs."
But it's about more than just economics, said Perkins, 38. It's about inspiration, history and being part of something historic.
"I want to design something that's going to be part of the Olympics," he told AFP.
Earlier Friday, President Barack Obama and his wife Michelle, a Chicago native, flew to Copenhagen to make the case for their cherished city to host the Games, as it competes against Rio, Tokyo and Madrid for the bid.
"I never really had any roots until I came to Chicago and discovered this most American of cities... It is a rich tapestry of neighborhoods. If you choose us we walk this path together," the US president said.
Obama said Chicago -- following Atlanta as the last US city to host the Summer Olympics in 1996 -- would allow America to restore its tainted image, "to show America at its best... that the USA is open to the world."
Michelle Obama used her father as her inspiration for bringing the Games to her hometown.
"Even when he was increasingly suffering from multiple sclerosis he would struggle on his crutches and play with us and he taught me a mean right hook," said the First Lady, who was born and raised in the South Side of the city.
"I am not just asking you to give us the Games as a Chicagoan or as an American but also as a daughter. My father would have been so proud to see us here bidding for the Games."
Olympian and Dream Team basketball player Scottie Pippen insisted that the support of the Obamas would help tip the balance.
"Anyone who thinks this city isn't ready for 2016, they're kidding themselves," Pippen told the cheering crowd.
"I know firsthand this city really supports their professional teams. They support their athletes and we'll be ready for 2016."
Three-time Olympic gold medalist swimmer Rowdy Gaines also on hand to rally the crowd and urged people to put on the orange Chicago 2016 T-shirts they were given as they walked in.
"When we win this plaza is going to be beamed around the world," Gaines said. They say three billion people will be watching. So if you ever wanted to be on TV, this is your chance!'
The International Olympic Committee earlier Friday launched its key meeting to choose the host for the 2016 Olympics, with Chicago the odds-on favorite heading into the vote.
Chicago bid leaders say the strength of their proposal lies in the city's geography and experience hosting major sporting and cultural events in its lakeside parks.