Walking in the old-port, Fine Arts Museum for sure, but if you prefer contemporary arts, the MAC is good https://macm.org/I'm not arriving until Wednesday, so I will have to fit in my sight seeing in between practices and some of the earlier groups.
@4everchan, what do you recommend for sight seeing? I've only been to Montreal once before. I'm super happy I'm staying right near Mandy's salads. I ate one of their salads the last time I went and it was so good. I'm also right near the Fine Arts Museum, so may check that out as well.
have a look here : https://www.timeout.com/montreal/things-to-do/montreal-attractions
I'd pick
1) Old Montreal
3) Plateau (my favourite neighbourhood ! It's the best !!! )
4) The bridge is lit and it's super nice to see... but you don't have to make it a special outing as you could see it from afar
DO not bother with the Village at 6... it 's no longer nice... very big problems in that area right now since covid.. relatively unsafe at times.
7) you can see from visiting 1)
12) Notre-Dame
14) is very good (biodome) and if you go there, it means you will see 13 (Olympic stadium)
15) is nice and can be done by visiting 1)
18) is the Oratoire as @Arriba627 mentioned : what is nice with it is the view point as it is located on the Mount-Royal
21) if you like Smoked meat... it's iconic
of course, you should have a real bagel and a real poutine