Those who look down from the heights conjecture about what is happening in the city; they wonder if it would be pleasant or unpleasant to be in Irene that evening. Not that they have any intention of going there... but Irene is a magnet for the eyes and thoughts of those who stay up above.
... Kublai Kahn expects Marco to speak of Irene as it is seen from within. But Marco cannot do this: he has not succeeded in discovering which is the city that those of the plateau call Irene. For that matter, it is of slight importance: if you saw it, standing in its midst, it would be a different city. Irene is a name for a city in the distance, and if you approach, it changes.

For those who pass it without entering, the city is one thing; it is another for those who are trapped by it and never leave. There is the city where you arrive for the first time; and there is another city which you leave never to return. Each deserves a different name...
Invisible Cities.

Map of Manhattan via.