Much of the NATO cost went toward security, including police overtime.
May's historic NATO summit helped put Chicago in the world's spotlight but it also managed to rack up a significant bill.
According Mayor Rahm Emanuel's office, the cost of putting on the event was $27.5 million, the Chicago Tribune reports, but $20 million was covered by the federal government.
The remaining cost won't be coming out of taxpayer's pockets, however. Around $33 million was raised via private donations for additional expenses, leaving a surplus of more than $10 million, according to the newspaper.
A mayoral spokeswoman says some of that money will be used for park improvements and other projects around the city, and an additional $4 million remains at Emanuel's disposal.