To me, Atlanta has long been the invisible city. Like anyone who flies with regularity (as I used to do pre-Covid), I’ve changed planes too many times at Hartsfield-Jackson airport. My joke about it is that no one has ever seen the outside of its seemingly infinite terminals—that, like certain freaks of topology (Google “Klein bottle”), it has no exterior.

In truth, though, I have occasionally escaped the confines of the endless terminals and ventured into the city itself. I once spoke at a conference at the AmericasMart (né the Merchandise Mart) in downtown Atlanta, but I can’t recall a single thing about what the place looked like, inside or out. Prior to a weekend in Atlanta this past October, my previous visit to the actual city was in 2003, and I can only reconstruct the details of that trip by reading what I wrote about it at the time.

I live and breathe cities. My memory is a vast trove of urban places, famous and obscure, large and small; I can go on at length about the graffiti-filled tunnel through which Little White Oak Bayou in Houston sneaks under a massive highway interchange, or the water tower that’s also the world’s tallest free-standing Corinthian column, found smack in the middle of a St. Louis intersection. So it is a little weird that, until I visited Atlanta again this past fall, my visual recall of the city was almost nonexistent. This is especially peculiar not just because I’ve found reasons to respect and admire even the most chronically unloved American cities, but because the first work of architecture that truly moved me was by a man who was, for a considerable time, Atlanta’s one noteworthy homegrown architect and developer: John Portman.

In the mid-1960s, Portman began the project of rebuilding a 2.5-million-square-foot chunk of downtown Atlanta (which eventually mushroomed to almost 19 million square feet) in what became his signature style: masonry towers that are inert on the outside and, seemingly, like the airport, all interior and no exterior. Portman’s theory, circa 1967, was that urban life as it once existed—the hustle and bustle of pedestrians visiting local shops and socializing on the pavement—was over. Streets were inherently dangerous and ugly, and what was needed instead were “total environments” in which “all of a person’s needs are met,” preferably without ever leaving the building.

As an 18-year-old college student on a summertime jaunt to San Francisco in the 1970s, I wandered into Portman’s brand-new Embarcadero Hyatt, with its dramatically raked 17-story atrium. To me, it looked like an M.C. Escher drawing come to life, and more than the other architecturally noteworthy buildings I’d previously visited—mostly museums like the Guggenheim or the monuments in Washington, DC—it instilled in me a sense of extraordinary possibility.

Of course, Atlanta isn’t John Portman’s city anymore—at least not entirely. One long, circular stretch of it is has been radically transformed by a very au courant piece of urban design: A linear park known as the Beltline, built incrementally since 2008, now encircles much of the city and has spawned new clusters of residential development along its path. The concept would be familiar to Portman, who believed he was building pedestrian-oriented villages—except his pedestrians were supposed to do their walking indoors, in corridors and across sky bridges, while the Beltline is outdoors, a long, narrow environment tracing the path of an old freight rail line. When it is completed, the main loop will be 22 miles long. And though it hasn’t yet inspired Atlanta to make its ordinary streetscapes more hospitable to pedestrians, the Beltline has become a magnet for walkers and bicyclists (who often drive to get there). Like New York City’s High Line, Detroit’s Joe Louis Greenway, or Dallas’s Katy Trail, the Beltline doesn’t just provide a recreational conduit; it changes the way people live in the city around it.

My interest in the Beltline was sparked in 2017 when I interviewed Ryan Gravel, whose graduate thesis at Georgia Tech proposed repurposing the disused freight line that encircled downtown as the site of a linear park and light rail line. After his graduation in 1999, he began the work of making the concept a reality. With the initial support of a single Atlanta councilwoman, Gravel and a growing number of planners and community activists gradually built momentum and found financial support for the project in the form of a Tax Allocation District, meaning that the project is now supported by the development along its path. The TAD also funds affordable housing along the Beltline.

Invited to speak at a conference at Georgia Tech this past fall, I finally got a chance to see it. After getting my bearings, I arranged to meet Gravel at a spot along the Beltline so we could explore it together. I also invited a fellow conference participant, Maurice Cox, whom I had last spoken to when he was head of Detroit’s Department of City Planning, a role he would subsequently play in Chicago. Among other things, Cox is remembered in Detroit for meeting with a group of activists in 2016, soon after his arrival the year before, and declaring that he wanted to make the Motor City “America’s best city for bicycling.”

We rendezvoused outside a food hall called Krog Street Market, after which Gravel walked us south, through the graffiti-filled Krog Street Tunnel and alongside the Hulsey railyard, a disused 70-acre CSX facility that may someday be redeveloped as a walkable neighborhood and a major stop on the Beltline’s light rail loop. Gravel no longer has any official ties to the project, but he’s still concerned with its future, particularly whether the light rail line he envisioned will ever happen. He also pointed out that there are very few spots along the Beltline’s path that have blossomed into full-fledged public places, with the landscaping and infrastructure you’d expect from a real park.

Nonetheless, the section of the Beltline we walked, on Atlanta’s affluent Eastside, appeared to be an overwhelming success. Everywhere there is new housing, both market-rate and affordable. We were also impressed by the intensity of the activity all around us: the sheer number of people taking pleasure in walking, biking, riding scooters (Cox tells me that his Atlanta relatives habitually head to the Beltline to get some exercise after big holiday meals), or dining in, say, an open-air taco shed. And unlike New York’s High Line—which, because it’s elevated and painstakingly crafted, feels like someplace very precious—the Beltline is at street level and looks, in most respects, very ordinary. This elemental piece of infrastructure, with some stretches paved and others not, mostly feels organic. If I didn’t know better, I would think it had always been there.