CHICAGO (AP) — Chicago’s third-tallest skyscraper could get a $185 million observation deck and an attraction that would dangle visitors over the building’s edge.

The Chicago Tribune reports that Aon Center officials unveiled the observatory plans Monday. They include a feature called the Sky Summit, gondola-like compartments with windows and see-through floors that would be lifted over the building’s side.

Officials hope to take advantage of the center’s location near Millennium Park.

Chicago already has observatories at Willis Tower and the former John Hancock Center.

Steve Sales is principal of the New York-based 601W Cos., the Aon Center’s owner. He says officials believe there’s a market for all three attractions.

601W Cos. estimates the proposed project would take two years to build and could attract 2 million visitors annually.

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