UrbanToronto Forum member androiduk recently posted a zoning review status that was submitted for the Atrium on Bay, calling for a five-storey addition to be constructed atop the current building and the possibility of a new Target store included in the plans.
The zoning review would see the Atrium receive a much-needed reinterpretation, although it remains unclear where the addition would be placed, if accepted. The current building was built in the mid-1980's, designed by Toronto favourites Page + Steele Architects. The complex is composed of three terraced sections, coming in at 15, 14, and nine storeys.
The building is located on prime retail space, directly across from the Eaton Centre, connected to the PATH system (which is currently undergoing an expansion), and links Dundas subway station with the bus terminal at Bay and Dundas. While the interior is definitely starting to show its age, it contains one of the more unique public spaces within the city, defined by large atriums bringing tons of natural light into the retail space and lower levels. Keep an eye out on the project forum here for further developments in this story.