The urban worst-case scenario known as Detroit has been compared to Pompeii and circa 1946 Hiroshima. But the erstwhile Motor City wasn’t destroyed by a natural disaster or an atomic bomb. It succumbed to sheer carelessness. It’s as if a major metropolis shriveled in the dryer or rotted in the back of the refrigerator.

Look, for example, at the large-format photographs of the city’s former Cass Technical High School building, on display at the National Building Museum. The images, made in 2009 by Andrew Moore, show not just an abandoned structure, but forsaken desks, beakers, scales and Bunsen burners. Most appear serviceable, but no one bothered to move them to the new school, which was built on the same campus.

Much the same thing happened, on a larger scale, all over the city. Stuff was left in a heap as people rushed to the ’burbs. Detroit has lost about two-thirds of its 1950 population of 1.8 million, and it was recently estimated that one family leaves every 20 minutes.

Suburban flight is a complicated matter, of course. It involves cheap land; changing lifestyle trends; and federal, state and city policies that worked against one another or didn’t work at all. (Look up in the sky! It’s an elevated people-mover in a city of unclogged streets and few inhabitants.) Also implicated are two of this country’s least tractable problems: racism and poverty.

That’s more than can be expressed in a single photographic show, or even two. But the Building Museum’s twinned exhibitions capture a lot of what happened to Detroit and thus are suitably infuriating.

The large-format pictures constitute “Detroit Disassembled: Photographs by Andrew Moore.” In the adjacent galleries is “Detroit Is No Dry Bones: Photographs by Camilo Jose Vergara.” Moore’s photographs are epic, detailed and eerily detached. There are no people in them. Vergara’s are warmer and more conventionally journalistic. They show signs of life.

Both photographers document some of the same places, notably Michigan Central Station, which has been unused since 1988. It’s such an iconic 20th-century mess that it has appeared in at least seven feature films and documentaries (including the recent “Detropia”). The edifice, which combines a Grand Central-like station with a towering office building, is shown with snowdrifts inside, and landscaped with a raised garden that doesn’t much change the overall impression of the empty hulk.

Other prime spots for what some locals call “ruin porn” are looted houses, residential lots returning to prairie and the massive former Packard plant, which operated from 1903 to 1958. There’s also plenty of grand, nonindustrial pre-modern architecture, much of which would be lovingly renovated tomorrow if only it were in a city with a stable population.

In 1995, near the beginning of Vergara’s fascination with Detroit, the photographer proposed that several blocks of empty downtown buildings be stabilized and left as “an American Acropolis.” Yet of the two photographers, it’s Moore who takes the more Olympian view. And when he gazes down on Detroit, he sees only loss. His pictures are too beautiful to be compared to pornography, however. Maybe they could be termed “ruin erotica.”

It seems unlikely that Moore would notice, let alone photograph, many of the things seen in “Detroit Is No Dry Bones.” Vergara depicts storefront churches, non-chain fast-food restaurants, and lots of signs and graffiti — commercial, vernacular and art-schooled. (The show’s title comes from a piece painted by four visiting Dutch designers, who took the phrase from a local preacher’s sermon.) The Chilean-bred photographer shows workers and small businesspeople, the structures they’re dismembering and the ones they’re trying to resuscitate.

Vergara also revisits sites, not always to find encouraging developments. Sometimes, a cleaned-up structure has gotten dirty again, or a place that’s been pruned has become overgrown once more. A follow-up trip can reveal nothing but an empty lot. One sequence shows a structure “under angelic protection” after a local art instructor added celestial statues to the facade. Eight years later, the heavenly tribunes have disintegrated.

During a walk-through of his show, Vergara noted that dying Detroit found a new life via cyberspace. Artists began embellishing empty structures — Tyree Guyton, for one, has been painting dots on East Detroit buildings since 1986 — and then publishing the handiwork on Web sites. The virtual displays (and low rents) drew artists to live in the city. While pheasants thrive in the outlying neighborhoods, central Detroit has the potential to become, perhaps, a Hoboken to the Manhattan of Renaissance Center — the self-contained, very 1970s complex that absorbed downtown’s remaining vitality.

The possibility of a revived Detroit interests Vergara but maybe not Moore. A vacant industrial wasteland better suits the latter’s disinterested eye. You don’t have to look at the urban debris to see Moore’s taste for the ominous; just check out his looming gray skies.

Moore seeks the ideal symmetry of shiny and drab, green grass and rusted metal. He finds it in such surrealist ready-mades as a half-melted clock — another memento of Cass Technical High School — or a large oil tank whose reflection is shattered by an uneven series of puddles. A tidied-up Detroit wouldn’t offer such elegantly decrepit vistas.

After all, lots of cities have gone through cycles of decline and reclamation. But a world-famous ruin is a rare and wonderfully photogenic thing.

Jenkins is a freelance writer.

Detroit Is No Dry Bones: Photographs by Camilo Jose VergaraDetroit Disassembled: Photographs by Andrew Moore

On view through Feb. 18 at the National Building Museum, 401 F St. NW; 202-272-2448;