We walked from the Ritz-Carlton and took the stairs up to the top observation point. It took us about 45 minutes to get to the top, but we got lost a few times. (I would suggest using the rue Peel entrance; it's easier to follow the route than the one we took). The view is absolutely fantastic--a sweeping panorama of Montreal.
One should keep in mind that the route to the top has A LOT of stairs, and is not for the faint of heart. I still recommend it, and the walk down is a lot easier than the walk up.
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