Why do memories stay with us? Calvino explores this question in his chapter “Cities & Signs 2,” in which Marco Polo describes his visit to the city of Zirma.

Zirma is a city that sticks in the mind: “Travelers return from the city of Zirma with distinct memories: a blind black man shouting in the crowd, a lunatic teetering on a skyscraper’s cornice, a girl walking with a puma on a leash.”

The secret of these memories, is that each sight is repeated so that it might stay with the viewer:

Actually many of the blind men who tap their canes on Zirma’s cobblestones are black; in every skyscraper there is someone going mad; all lunatics spend hours on cornices; there is no puma that some girl does not raise, as a whim. The city is redundant: it repeats itself so that something will stick in the mind.

Italo Calvino, Invisible Cities, Cities and Signs 2

For some reason Polo sees through this city in a way that other visitors are unable to:

I too am returning from Zirma: my memory includes dirigibles flying in all directions, at window level; streets of shops where tattoos are drawn on sailors’ skin; underground trains crammed with obsess women suffering from the humidity. My traveling companions, on the other hand, swear they saw only one dirigible hovering among the city’s spires, only one tattoo artist arranging needles and inks and pierced patterns on his bench, only one fat woman fanning herself on a train’s platform. Memory is redundant: it repeats signs so that the city can begin to exist.

Italo Calvino, Invisible Cities, Cities and Signs 2

Here Calvino suggests that the city lives a double life – it is, itself, and at the same time there is a new city recreated in the mind of the visitor. Or perhaps we should say there are an infinite number of cities recreated individually in the minds of visitors, just as the visitors described by Polo hold in their minds a different Zirma than the one belonging to him.

Thinking of memory as built from redundancy rings true to me. I think of the waterfall in my childhood backyard. Why can I remember it so vividly? Just beyond the outflow of the pond there was a concrete wall, maybe eight feet high, over which the water flowed and dropped. We would cross it, edging over it with our feet sideways, slide-stepping them across the rough pebbled grey concrete, pushing perpendicular to the flow of the water, the fear of falling over the wall to the slab below, and the way that fear would yield to the rush of excitement each time I reached the far end.

This memory is so firmly planted in my mind because of its redundancy, like Calvino’s Zirma – the repetition of the experience means that I have carried that waterfall with me for all these years.

Yet if existence is carved out through memory, and repetition or redundancy are what allow memories to solidify, at least for a time, repetition is also the enemy of memory. Think of a time you parked your car regularly (or semi-regularly) in a particular structure or lot. The more memories of doing so you possess, the harder it is to find your car on any individual visit, because the layered memories interfere with the specific memory of this trip. I have traded the specificity of any single visit to that waterfall from my youth for a generalized waterfall, the somehow generic specific experience of crossing that strip of concrete. Thus we trade a kind of truth for a composite lie. And yet as Calvino suggests, perhaps the only way to hold onto anything is by making this kind of trade off….