The UNESCO-listed old town on the left bank of the Salzach is the postcard Salzburg — Getreidegasse, the cathedral squares, Residenz, St Peter's, and the Mönchsberg cliff with the fortress on top. Cars are banned from almost every street, which makes it one of the most walkable old centres in Europe.
The southern half is the ceremonial city: cathedral, palaces, festival halls. The northern half — Getreidegasse and its side-streets — is the commercial city: shops, courtyards, cafes. Both can be walked in a single morning, but the texture rewards three or four leisurely days.