I was mentioning in the comments of a post yesterday that Montreal has an underground city.
I stumbled upon an old photo showing what one of the Churches near McGill looked like during an expansion of the underground.
The first photo is one on display under the church, as part of the underground city.
The second is one I took myself on the surface.
Nothing super exciting underneath, at least that I've seen. Mostly large hallways with stores like this:
