You know that a river runs through a city (as opposed to tangentially touching it), when you constantly cross it, as a tourist or in daily life.
I don’t do that in Vienna. Yes, I cross the Danube by Underground (even on a bridge actually), when I need to go to the center or to the railway station, but that’s not what I mean. In Budapest the river equally divides the center. The density of bridges is high, and you need to use them all the time. So I did.