There's been quite a stir a few blocks from my apartment on Chicago's northwest side. According to many of the neighborhood's pious, the Blessed Virgin Mary has manifested in a most unlikely spot. On the concrete wall alongside W. Fullerton Ave., in the underpass beneath the Kennedy Expressway, a salt stain has emanated from a leaky crack, taking on, as some see it, the form of St. Mary. Pilgrims are turning out in large numbers to behold Our Lady of the Underpass, as the apparition has been dubbed. So I grabbed my digital camera and walked to the site to have a look for myself.

When I arrived in the early afternoon, between thirty and forty people were gathered in front of the sacred image, where dozens of candles, bunches of flowers, taped-up photos of loved ones, and icons of Mary were clustered in a makeshift altar. A couple of squad cars were on hand to keep things in order, and the camera crew from a local television station was filming the scene. Indeed, this phenomenon is a media favorite; the Chicago Tribune has featured several articles on the spectacle, and televised news reports have run regularly. And, of course, AM talk radio has not overlooked this extraordinary, perhaps supernatural, occurrence.

One of the Tribune articles alluded to a feature of this happening that I found particularly conspicuous on my visit, namely, the prevalence of digital cameras. Reporter Mary Schmich asks, "What does it mean if the Virgin Mary is clearer on a cell phone screen?" She continues in religiously evocative language: "What was with the cell phones? Dozens were being held aloft like candles in a vigil, the eyes of the enraptured tilted toward a constellation of [miniature] screens. 'You can see it clearer on the cellular,' said ... Carmen Lopez, 38, who was on her third visit to the miracle. Sure enough. Our Lady of the Underpass looks her best on a cell phone" ("Real or Not, Images Bring Us Together," Chicago Tribune, April 20, 2005).

Reviewing the slew of digital photos I took, I had to concur. Further corroborating the impression is one of the most compelling renditions of the image, captured by an AP photographer, found in the Tribune: a photo of Mary in another person's digital photo -- a copy of a copy of the real thing.

So what does it mean that the Virgin Mary is clearer on a cell phone screen? While the Tribune article raises the question, its otherwise thoughtful author doesn't offer much in response. I want to suggest a way to interpret this apparition and the implications of its technological enhancements.

Our Lady of the Underpass appears on a concrete wall, and was at first hemmed in on either side by graffiti that have since been obscured by religious fliers or washed away by pious purifiers. One graffito rooted for the Cubs, while another had something to say about Satan's amorous preferences. In any case, the milieu in which Mary has appeared suggests that the image might best be read as a sacred graffito. From this perspective, Our Lady of the Underpass is the writing of God's hand on a concrete wall -- a message (of hope?) to the Catholic city-dwellers in the form of a beloved mediator.

Graffiti are generally regarded as the lowbrow medium of vandals and street artists who make do with what's cheap and readily available in the city: spray paint and concrete. Unlike most art that hangs on the white walls of a gallery, the sometimes vague and sometimes ornate "script" of graffiti is site-specific. Inseparable from its context, it can't be displaced. Its aura, to use cultural critic Walter Benjamin's term, is attached to its unique presence in a specific spot.

And yet, this spot on the wall is being reproduced endlessly in digital cameras by religiously fervent folks whose photo-taking is likely an extension of their piety. In fact, I would go so far as to suggest that the availability and portability of digital cameras is underwriting pious behavior here; some of the pilgrims are inspired by the possibility of taking home pictures of the apparition. (The same might be hypothesized in regard to the droves showing up to behold -- and photograph -- the body of the recently deceased pope).

Our Lady of the Underpass is thus a kind of sacramental catachresis: a hierophany in a lowbrow medium, an original image at once tied to the spot and infinitely reproducible, displaceable. And this tension between the cultic value of the original and the proliferation of its reproductions speaks to a wider shift in religious and cultural values -- for today virtual substitutions are often held to be as real or realer than the "originals" of which they are "copies."

Perhaps this apparition exemplifies a form of mysticism in the age of digital technology: From the dim, grotto-like viaduct in which she originally appeared, Our Lady is now virtually manifested in homes all over Chicago and across the nation, enhanced by a digital aura.

Jeremy Biles holds a Ph.D. from the University of Chicago Divinity School and is the Managing Editor of Sightings.