CHICAGO (CBS) — Firehouses around Chicago observed a moment of silence Sunday, in honor of their fallen colleagues, who died in the line of duty on Sept. 11, 2001.

They saluted the American flag at half staff.

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Mayor Rahm Emanuel said the tragedy brought a sense of national unity. “The selfless act, where other people were running down this flight of stairs, ran up the flight of stairs to serve their fellow citizens.”

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“It’s always in the back of your mind what happened back then,” a fire official said. Yeah, it happened in New York, but it could happen here also.”

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