In a city filled with amazing Churches, St. Patrick's Basilica is my absolute favorite!! A couple of months ago, I returned here for the first time after 20 years. This Catholic church is still beautiful outside, and even more amazing inside.
My French speaking skills are not good. I find it very convenient to attend mass here because most of the masses are celebrated in English.
If you find yourself in Montreal, then make sure to visit St. Patrick's Basilica. It is not the most popular Church, but it is still impressive.