I liked these stairs more when they were incomplete: http://www.flickr.com/photos/vikpahwa/15747912008/
The Andrews Building containing these stairwells was designed by the Australian architect John Andrews in 1965 who later went on to design the CN Tower.
Note the raw concrete (beton brut) look furnished by the wood forms in which the concrete was poured in place.
The attributes that make this building unique include the circular plan, the engaged inverted engaged catenary arches on the lower wall and the taller engaged catenary arches on the upper wall with fins that extend beyond the original roofline. Unfortunately, the recently added metal penthouse (or cap on top) obscures these fins from view and diminishes the brilliant original design that you can see at http://commons.wikimedia.org/wiki/File:Pumping_station_in_Ashbridges_Bay_Toronto.jpg. This pumping station is officially known as the Mid-Toronto Interceptor Pumping Station but being a part of the Ashbridges Bay Treatment Plant, it goes by the name Building T.