A plan created by architects Solomon Cordwell Buenz (SCB) and developer 601W Companies that aims to bring the tallest exterior glass elevator in North America to the Edward Durell Stone-designed Aon Center in Chicago has been approved by the city's Department of Planning and Development. The project was first announced in March of 2019.

The Chicago Tribune reports that the $185 million project will create the city's third sky-high observation platform, following those at the Willis Tower and John Hancock Center. The project aims to bring a 1,000-foot exterior elevator to the northwest corner of the tower that will ferry passengers from a new ground level pavilion up to the top of the tower. 

For the observation deck, the project team is partnering with Legends, a New York City-based entity that negotiated a 20-year joint venture agreement to co-own the observatory with the developer. Legends also operates the observatory at the One World Trade Center tower in New York City. 

The two-story observation platform will take over spaces at the top of the tower formerly used for mechanical systems and will instead offer a variety of viewing areas, concessions, and even a thrill ride that will bring visitors up to the very top of the 1,136-foot-tall tower for 30 to 40 seconds at a time, according to The Chicago Tribune. 

The tower, completed in 1973, is the city's third-tallest building, a rank it will lose as work is completed on Studio Gang's forthcoming 1,191-foot Vista Tower. The Aon Center observation platform team expects to begin work on the amenities late this year with a planned completion date of 2022 slated for the project.