Last month an investor bought the old Harvest State grain elevator off Hiawatha Avenue for $23,000. He says he’ll turn it into housing.

Possible obstacles, according to a Star Tribune story: “atmospheric conditions like oxygen deficiency and poisonous gases.” Assuming the remodeled building can boast, “Now with less asphyxiation!” when it opens, its proximity to light rail might be a draw.

It would seem cheaper to knock it down. It’s not as if the Hiawatha structure is the only abandoned reminder of the Mill City’s past.

The area around the University of Minnesota has a collection of enormous elevators, spattered with graffiti, surrounded by weedy lots. A featureless slab of brick six stories tall with a long tin shed perched on top. Undulating walls of gray concrete daubed with paint to cover the vandals’ scribbles. Rusty streaks where the elements have pecked a hole and revealed some iron that bleeds when it rains. Bricked-up doors, boarded-up windows.

You can imagine them as cliffs crafted by a million years of graceful erosion, or remnants of an early civilization that loom over the modern streets like the pyramids. They weren’t built to be beautiful. They were built to be useful. But now many stand abandoned.

Are they all doomed? Should we care? It’s not as if these structures can’t be re-purposed. You’ve probably seen one of the most prominent and important examples as you drove Hwy. 100 by Excelsior Avenue. The tall tower that says “Nordic Ware” — that’s a grain elevator, repurposed as a sign. It was the first round concrete elevator built in the United States, finished in 1900. Grain magnate Frank Peavey commissioned the structure to see if concrete could bear the weight; Charles Haglin, architect of City Hall, designed it.

The poetically named Peavey-Hamlin Experimental Concrete Grain Elevator was never used after the experiments, but its fame spread: The Minnesota Historical Society’s website on the structure notes that Le Corbusier himself hailed the great gray pylon as the “magnificent First Fruits of the new age.”

St. Louis Park had other elevators along its railroad tracks, some as massive as the ones by the U. The Commander Larrabee complex was demolished in 1989, and apartment buildings rose on the spot. The St. Louis Park history pages note that the complex has “a rounded shape to pay homage to the monolith they replaced.” A nice gesture — but you wouldn’t know unless they told you.

Conversion into housing is possible — just look at the Calhoun Isles Condominiums on Dean Court, which converted old silos into lake-view dwellings. If you tell someone that they used to be grain elevators, people say: Ah, I can see it. But once you punch windows and balconies into the structures, they don’t look like grain elevators anymore. They look like buildings from the 1960s or ’70s, when circular forms were in vogue.

An office building turned into a hotel still looks like an office building. A historic factory remade into a shopping complex still looks like an old industrial facility with a new purpose. But a grain elevator is meant to be one thing, and that’s an elevator for grain. Making it anything else erases its identity for the sake of preservation.

The main appeal of the grain elevators is the very thing that keeps them from being reused: They don’t look like places where people are supposed to go, let alone live. They make the Bastille look like Versailles. Abandoned in empty lots, ignored by trains they once filled that now clatter past without stopping, they are remote and forbidding, brooding bulks that would prefer to be left alone.

As the U grows and more residential units fill in the old industrial area, someone will propose better uses for the sites, and that probably means they’ll thunder down into rubble. The new Surly brewery abuts an old steel elevator, which gives the neighborhood a certain industrial credibility prized by those who want their beer consumed in an authentic urban environment. But 10 stories of apartments would do more for the area than a stoic steel silo, and if the adjacent elevators were converted to apartments they might have all the monolithic charm of a Soviet housing project.

But we should save something, no? Let’s say the city keeps one around for historical purposes. The ADM Meal Storage Elevator, the one that has the graffiti artists’ name “United Crushers” painted at the top in huge letters. It’s visible from a great distance, a big blank canvas. Imagine projectors that paint it with light and color, a huge shimmering screen visible for miles. Movies in the summer, with your smartphone as a speaker. Sunrise hues in the morning, sunset reds at dusk. Huge old ads for flour and bread.

Or we could just wait for a spectacular plan that renovates the elevators and honors their original stark aesthetic. No hurry. As you stand among the silent buildings by the U on a brittle February day, they remind you of great ships stuck in the ice. They’re not going anywhere soon.