The city exists

   "The harbor faces north, in shadow. The docks are high over the black water, which slams against the retaining walls; stone steps descend, made slippery by seaweed. Boats smeared with tar are tied up, waiting for the departing passengers lingering on the quay to bid their families farewell. The farewells take place in silence, but with tears. It is cold; all wear shawls over their heads. A shout from the boatman puts a stop to the delays; the traveler huddles at the prow, moves off looking toward the group of those remaining behind; from the shore his features can no longer be discerned; the boat draws up beside a vessel riding at anchor; on the ladder a diminished form climbs up, vanishes; the rusted chain is heard being raised, scraping against the hawsepipe. The people remaining behind look over the ramparts above the rocks of the pier, their eyes following the ship until it rounds the cape; for the last time they wave a white rag.
    "Set out, explore every coast, and seek this city," the Khan says to Marco. "Then come back and tell me if my dream corresponds to reality."
    "Forgive me, my lord, there is no doubt that sooner or later I shall set sail from that dock," says Marco, "but I shall not come back to tell you about it. The city exists and it has a simple secret: it knows only departures, not returns."

- Italo Calvino, Invisible Cities