The Place d'Armes square in Old Montreal, in front of the Notre Dame Basilica, was totally leveled this past summer. And what a sight it was. The square as it used to look like can be seen in the bottom picture (from google maps).
Considering that it took the city forever to update Dorchester Square in Downtown Montreal, I didn't go back in Old Montreal to see if it was completed yet.
Addendum: I just read an article at La Presse about this and the square has been like this since september 2009 and they stopped the renovations during the summer of 2010, at the height of tourism, and probably only restarted this fall. It's amazing that it's taking longer than the Dorchester Square renovations. Also, the square was spruced up back in 1960. The last photo shows a computer simulation on how it's going to look like. 2 years to lay down some pavement.
Second addendum: I just learned that the renovation was delayed because while digging up around the square, they found archeological finds, like an old sewer and a wall that was part of one of the first buildings built in the area.