The McGill Ghetto isn't a ghetto and never was — it's the student quarter that grew below the campus, named with the dark humour of people who couldn't afford to live anywhere nicer. What it is, properly, is the densest run of Victorian greystone in Montreal, kept alive by the cheapest rents in the centre and the people willing to pay them.
Start at McGill's Roddick Gates on Sherbrooke and turn into the grid. Rue Prince-Arthur, pedestrianised since the 1980s, still runs its terraces east toward the square. But the real walk is the side streets — Sainte-Famille, Hutchison — where the grey limestone rows stand bay-windowed and stair-fronted, built for the bourgeoisie and inherited by undergraduates.
The Milton-Parc co-op blocks are the quiet triumph: houses that organised against the wreckers in the 1970s and became Canada's largest housing co-operative, saved by looking ordinary. Stop for coffee where Parc meets Milton, then end at Carré Saint-Louis, the poets' square around its fountain. The metro is at Place-des-Arts, south through the trees.