The smaller Chapel of Notre-Dame du Sacré-Cœur was damaged by fire in 1978 and was rebuilt afterward, but the main basilica interior is still largely original. Or so I believe.

A quick check with an older family member who used to frequent that cathedral a long time ago confirms that the pipes were for hot water heating, with radiators below the "prime" seats.

You'll notice that most of the pews in the central rows have a door and a little plaque. That was because they were private seats for wealthy Montreal families. A "generous" contribution to the parish got your family a private pew in a prime well heated location and a plaque with your family name for all to see.

As a Montreal resident I can certainly attest to the need for heat, it was 10 degrees F this morning. Pipes of this type are very much associated with hot water heating and the proximity to the rows of pews, along with the unusual detail of doors to the pews which clear the pipes suggests that these pipes may have fed arrays of pipes that passed under the foot space in the seating areas which, with the little doors closed to block drafts, may have provided sufficiant heat to enable parishioners on a cold winters day (-10F is not unusual) to sit through the two hour long latin masses that were typical of the day. Just guessing though.

Be careful when you compare this photo with the modern views. The church was heavily damaged by fire in 1978, and most of the present interior dates from after the fire.

Those sure do look like pipes along both sides of the aisle. Could they be for heat? Hot water pumped from a boiler?

the fanciest zeppelin hangar in the world.

Can that be a pipe running along the floor next to the pews? So out of place if it is.

This photo is reminiscent of https://www.shorpy.com/node/6456

Great interior view -- would love to see a shot from the opposite direction of the Casavant organ (1891) in the rear gallery. (I'm an organist.)

This is one time when black and white really fails to do justice. Except for the pews and the central sculptures on the reredos and on the pulpit, virtually everything in this picture is either gilded or polychromed, including the ceiling. The pillars are polychromed and gilt in patterns. And they weren't finished, even then: the stained glass didn't arrive until the 1920s, and at some point someone apparently felt that the one blank area on the back wall of the apse above the reredos needed some decoration too, so they put a sort of celestial background on it-- gilded, of course. The replaced the altar with a different one which incorporates three reliquaries; need I say, gilt over every square inch of their Gothic revival surfaces?

I have to say, though, that Gothic revival skylights are something only the Victorians could have though of. And alas, the light fixtures among the pews are no longer with us.

The Organ can be heard and the present day interior viewed by clicking here.

As genuinely glorious as Montreal's Notre Dame is, in this case I'm referring to the Detroit Publishing Company's wonderfully detailed photo of the basilica's interior. I thought it would be pretty easy to find a comparable modern color photo, and was surprised to find that, of the dozens of photos available in Google Images, many of them taken by professional architectural photographers, almost none of the images comprised as complete and undistorted a record of the Basilica's interior features as Detroit's carefully adjusted view camera version. It is of course exciting but not surprising to learn that the primary color scheme is blue and gold. The Basilica's own website includes many fine detail images of the building's artworks and decorations, available at www.basiliquenotredame.ca/en/basilica/pictures.aspx, but no single interior view as technically accomplished as Detroit's. I did find one view online, despite its monitor-friendly horizontal format, that seems overall to come closest to the qualities of the Detroit image, taken in 2011 with a Nikon D90 by professional photographer Ash Henderson.