Many CTA Brown Line riders are curious about the classic silver 1960s Airstream trailer perched atop this office building. The former industrial structure was renovated in 1989 to house Chicago Associates Planners and Architects, a design cooperative led by architect Edward Noonan. Looking to add a whimsical amenity for employees, Noonan asked city officials for permission to hoist the trailer onto the roof, but was not taken seriously. With a rented crane, the trailer was lifted onto the roof, drawing an emergency response when the CTA mistook it for a derailed Brown Line train. In the years since, the Airstream "Conference Center" (complete with rooftop deck and skyline views) has hosted numerous events and parties.