As a flâneuse — one who drifts aimlessly for great distances through city streets — I like few pursuits better than setting aside an entire day, ideally no less than eight full hours, ideally with my best flâneur friend and fellow poet, Eric Plattner, to wander observantly from point to point.

Among the psychogeographer’s most beloved emotions is curiosity; curiosity is the engine that powers my meandering. Practically every intersection in our city offers layered opportunities for delving into mystery. But the patch of Chicago that most haunts me with the kind of just-this-side-of-unanswerable enigmas that I enjoy best is the gravelly and ill-kempt 6200 block of North Pulaski, at Granville, in the no man’s land that lies at the edge of Sauganash and north of North Park.

There, upon rusty posts, thrusts forth a low billboard demanding in black and white: “Who Is John Galt?” Ever since Eric and I first stumbled across it in the fall of 2015, I’ve wondered often about the query and its captivating combination of anonymity and specificity. For while no one seems to know who bought and erected the sign, passers-by might recognize the phrase as the opening sentence of Ayn Rand’s fourth and final novel, her 1957 paean to cold self-interest and unbridled laissez-faire capitalism, Atlas Shrugged.

While Rand’s sophomoric philosophy manages to be simultaneously repellent and silly, the sign itself is not uncharming: so homemade-looking, so earnest and pleading, so perplexing in its sparsely foot-trafficked location on the city’s Far Northwest Side, across the street from St. Odisho Assyrian church, a beige-and-brown brick structure dating to 1985 that doesn’t have a billboard but makes one wonder: Who was St. Odisho?

Just south of Capitol Cement, established in 1914, this intriguing block is, in fact, mostly covered in cement, but just to the southwest of the John Galt sign, the gravel gives way to a mud and grass tract.

Baudelaire called the flâneur the “botanist of the sidewalk.” Sometimes, though, the flâneuse must be a botanist of the overgrown vacant lot, the rocky parking lot, and the spot where the Jersey barriers and chainlink give way to the torn-up train tracks — the mesmerizing zone where everything is fluid, the space where flânerie meets parkour and one can’t merely saunter but must instead clamber and trespass a little.

Such is the case with this semi-hidden point of entry to the Weber Spur, still technically owned by the Union Pacific Railroad. While it, too, is a former freight corridor, this strip is no shiny and densely used Bloomingdale Trail. Although plans exist to pave it and connect it to the Valley Line and North Branch Trails, the spur remains, for the moment, desolate and rugged. One can walk the whole stretch and not see another human soul, even as one crosses viaducts above such busy streets as Peterson and passes such humming light industry as Precision Plating Company and Alarmist Brewing.

To slip through the chicory and Queen Anne’s lace onto the as yet not totally tamed spur at Pulaski and Granville is not to choose between a city walk and a nature one, but rather to realize that this binary — like most — is spurious and reductive. Of course a person can engage in both at once, and of course human beings are not separate from nature, but an inextricable part of it, no matter how much we build it over with concrete and train tracks and churches and billboards.

But back to this one block — this portal, this threshold, this container for questions. On the overwarm fall day when Eric and I discovered this ineffable intersection, they had not yet torn down the long-abandoned Handee Car Wash due south of the Galt ad. The soon-to-be-razed business’s changeable letter board had only a forlorn O remaining from whatever its original message had been. Around the vowel, a graffitist had Sharpied: “Your Actions Should Never Require Apology.” Never shall I apologize for my trespass through this matchless city block.

Kathleen Rooney is the author of the novel Lillian Boxfish Takes a Walk.