You've seen pictures of the Government Conference Centre before in this blog. It was once the main train station, linked to the Chateau Laurier (there to the left) by a tunnel below the street. These days the government makes use of the building, which is only open for Doors Open one weekend in the summer to the public.
I've taken pictures of it before, but not from this angle. In December, while taking Christmas light pics, I was passing through the National Arts Centre, and looked across the Canal at the building. The lighting drew my eye, so I stepped outside and took the shot.