CHICAGO – Organizers of the American bid for the 2016 Summer Olympics unveiled details of their plan Tuesday, promising a “spectacular” lakefront experience in the heart of the nation’s third-largest city.

Chicago’s plan clusters the majority of venues in four sites near downtown and along the shores of Lake Michigan, the world’s fifth-largest lake. Ninety-one percent of athletes would be within 15 minutes or less of their venues, and the Olympic stadium would be a six-minute drive from the village.

“The plan envisions the games woven into the landscape of Chicago’s century-old lakefront and in walking distance,” of many cultural and entertainment attractions and sports facilities, said Patrick Ryan, chief organizer of Chicago 2016.

“We believe Chicago promises a spectacular Olympic experience in the center of our city, in the heartland of this great country,” Ryan said.

Details of the plan – including 16 new permanent and temporary venues at an estimated cost of $900 million – were included in a questionnaire submitted to the International Olympic Committee and released by Chicago bid organizers.

It does not include a $1 billion athlete’s village, a public-private venture officials said will be built regardless of whether Chicago gets the games.

Chicago would hold the games July 22-Aug. 7, 2016. The paralympics would follow Aug. 18-28.

Chicago 2016 organizers estimated the games would generate $2.5 billion in revenue just from domestic marketing, including sponsorships, licensed merchandise and ticket sales. Organizers would give 500,000 free tickets to Chicago schoolchildren.

“The people of Chicago will experience these games like no people of any Olympic city before them,” said Doug Arnot, operations chief for Chicago 2016.

As Chicago released its bid documents, details also emerged Tuesday about the other six bid cities’ plans.

Tokyo said 95 percent of its competition venues would be within five miles of downtown. Organizers in Madrid, Spain, said the eastern edge of its city would be the focus for the Olympics. There would be 15 competition venues there, and all but five of the 30 venues would be about seven miles from the city center.

Chicago organizers said their plan for clustering the Games downtown and near Lake Michigan is unique.

“Compact is one thing, it’s where it’s compact,” Arnot said. “We’ve taken the very heart of the city and put so much of the games right there. That is unparalleled in any games.”

Besides Chicago, Tokyo, and Madrid, the other bid cities are Rio de Janeiro, Brazil; Baku, Azerbaijan; Doha, Qatar; and Prague, Czech Republic.

The IOC will whittle the seven applicant cities to an unspecified number of candidate cities in June. The IOC will select the host city in October 2009.