For the first time in a decade, the Windy City has the world's busiest airport.

With more than 585,000 flights taking off from O'Hare International Airport in the first seven months of 2014, the Federal Aviation Administration announced the Chicago airport has surpassed Atlanta's Hartsfield-Jackson International Airport as the world's busiest. It's the first time since 2004 that Chicago has held the title.

This data gives Chicago the title of the world's busiest airport based on the number of departing and arriving flights, butAtlanta's airport is probably still the busiestin terms of the number of passengers that fly into and out of the hub every year, CBS Chicago reports.

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Chicago Mayor Rahm Emanuel broke the news at the city's World Routes 2014 convention, the Associated Press reported. The mayor's office described the event as the largest for business-to-business aviation.

"O'Hare isn't just the busiest airport in the world, it's an asset for the City of Chicago," Emanuel said, according to the AP. "These new gains will help us attract new businesses and solidify our place as the best connected city in the U.S. and around the world."

The news comes after a long, rough weekend for O'Hare International Airport. Police say an FAA employee started a fire at the airport's offsite traffic control facilityFriday morning, leading to the cancelation of hundreds of flights.

Below is a countdown of the 20 busiest airports in the country. Each page in the gallery includes the FAA's information on how many flights have arrived and departed from each airport in the first seven months of this year.