CHICAGO (CBS) – As busy and chaotic as Saturday’s NATO protests and rallies were, Sunday could be even crazier.

A major march and rally are scheduled, ending up in Grant Park.

Police and most protesters say they don’t want trouble, and South Loop business owners surely don’t.

On Sunday, the protesters’ climactic day begins with a rally at noon at the Petrillo Bandshell. Then, as many as 15,000 people will hit the city streets.

“I think we’ll be peaceful, I can’t vouch for the police. I think our one big guarantee that the city will be on good behavior is the fact that so many camera people like yourself will be out there,” organizer Andy Thayer tells CBS 2’s Mike Parker.

The multitudes will head west on Jackson to State Street, then will move south a few blocks to Harrison. There will be extra police attention to one potential hot spot on Harrison: the MB Financial Bank, a symbol of the despised capitalist system.

After a right turn, the thousands will march almost two miles down the fabled Michigan Avenue, where many skittish business owners have boarded up the windows and facades.

The owner of La Cantina restaurant and bar hasn’t boarded it up — yet.

“I have concerns, but we’re going to stay open. We’re going to bring our sidewalk cafe inside. We’re going to be ready to board up in case anything happens,” John Mauro says.

The march will end a few blocks south of the restaurant at Michigan and Cermak. Just outside McCormick Place, a group of Iraq War veterans are pledging to give up their service medals.

Protest organizers had tried to convince NATO officials to come outside and receive those discarded medals. They got nowhere with that idea.

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