The Aon Center, Chicago’s third-tallest tower, will undergo a $185M renovation for the purposes of boosting tourism. This development, by the New York based 601W, will involve the addition of two 1,K’ exterior elevators in glass, as well as the addition of a rooftop observation deck to the existing structure, of which both are designed by our friends at Solomon Cordwell Buenz. Notable features will include a “sky summit”—a glass-encased pod which will hang off of the edge of the roof—as well as a cantilevered entrance hall at the base of the tower, and an observatory on the top two floors. In preparation for the additions the building’s HVAC system has been removed from the roof and placed elsewhere; also, two-thirds of the exterior columns on the Aon Center’s roof will be removed to allow better views from the deck. 601W has estimated that these additions will attract 2M additional tourists per year.