The building at 190 Bowery is a mystery: a graffiti-covered Gilded Age relic, with a beat-up wooden door that looks like it hasn’t been opened since La Guardia was mayor. A few years ago, that described a lot of the neighborhood, but with the Bowery Hotel and the New Museum, the Rogan and John Varvatos boutiques, 190 is now an anomaly, not the norm. Why isn’t some developer turning it into luxury condos?

Because Jay Maisel, the photographer who bought it 42 years ago for $102,000, still lives there, with his wife, Linda Adam Maisel, and daughter, Amanda. It isn’t a decrepit ruin; 190 Bowery is a six-story, 72-room, 35,000-square-foot (depending on how you measure) single-family home.

“I can’t believe it,” says Corcoran’s Robby Browne, an expert in downtown real estate. “I thought it was vacant.”

Even in the annals of “If only I’d bought that Soho loft in 1974” stories, this is extreme. In 1966, Maisel was a young artist, paying $125 a month for a 2,500-square-foot studio at 122 Second Avenue (his neighbors were Larry Rivers and La MaMa founder Ellen Stewart). But when his landlord raised the rent an unconscionable $50 a month, Maisel went to Jack Klein, a broker who, he says, had found spaces for Jasper Johns and Robert Rauschenberg. “We took an instant dislike to each other,” says Maisel. But the first property Klein showed Maisel was the abandoned Germania Bank, built in 1898, when the neighborhood was largely middle-class and German. “I said, ‘You got a lot like this?’ ” Maisel recalls. “Klein said, ‘This is why I hate photographers. They want the Taj Mahal and they want it for six bucks a month. No, I don’t have a lot like this.’ ”

Interpersonal friction aside, Klein convinced Maisel he could raise the money to buy the abandoned bank. That was the easy part. Then he moved in. The main floor was knee-deep in garbage and coated in soot. “I had to shovel shit against the tide,” says Maisel. He wasn’t getting a lot of support either; the Bowery was where people ended up, not where they aspired to live. “My parents cried,” he says. “Every single thing that can come out of a human body has been left on my doorstep. But it was more disgusting than dangerous.”

The house now feels like a dream world, or a benign version of the vast hotel in The Shining. Hallways go on forever. Rooms are filled with projects in various phases of completion. The renovations, mostly done by Maisel, are very “artists live here.” The air-conditioning, for example, is a building-wide network of giant plastic tubing (the kind used to ventilate greenhouses) that funnels cool air from six units, one on each floor. “It would have cost thousands to put in central air when I moved in,” he explains. The Mylar shades on the windows help keep the heat out; he and Linda make them in one of the rooms on the fifth floor.

Bedrooms, bathrooms, and dining are on the sixth floor; the kitchen was once where the staff cooked meals for the bankers. Linda cooks a lot, but when they do order in, “it’s a riot,” she says. “You have to wait downstairs and watch for the delivery person, because they’ll pass right by. Who is going to think that there is one person ordering from this building? Who wants to leave their bicycle outside?”

There’s only one elevator, the original copper cage from 1898. It’s gleamingly clean and in excellent working order, though it’s gotten stuck once or twice. “You know what a sign of love is, in this family? It’s if you come home and the elevator is on the ground floor,” says Linda. “Because that means whoever came home before you walked up twelve flights of stairs.”

Maisel uses the first, second, and third floors as gallery spaces for his photography and art projects. (This magazine’s first cover was a Maisel photograph.) The fourth floor, which Maisel once rented out to Roy Lichtenstein, is a work-in-progress. The fifth has various workshops, like the Mylar-window-shade room.

But there have been no major changes to the interior. It’s essentially unchanged from the Germania Bank that architect Robert Maynicke designed for the then-bourgeois neighborhood (it cost $200,000 to build). The original safe-deposit vault, still in the basement, is the size of a generous studio apartment; the marks on the main floor where the teller booths once stood are still clearly visible.

The building is its own mini-frontier, and, as of 2005, an official landmark. “Here’s the deal,” Maisel says. “If you have a window that needs fixing, you fix it. If I have a window that is broken, I have to repair it, with approval, the way it was done in 1898.” Upkeep is constant. “A typical day is first we might have to clean the sidewalks,” says Linda. “Because we’re responsible for the sidewalks in front of our building. Or the fire department comes for a walk-through, or the meters need fixing, or the boiler. Or the graffiti police come by.”

That’s another headache. The city wants the exterior graffiti-free, but it’s impossible: 190 Bowery is a mecca for street artists, as its neighbor 11 Spring was before it went luxury. Maisel tried scrubbing the building every week, but “it was like I was providing a fresh canvas for them.” Keith Haring used to cover the exterior in chalk babies, says Maisel, and that he liked, both for the spirit of the images and because they washed off so easily.

The building is still giving up its secrets. About a month ago, Amanda discovered a room she never knew existed. “It’s kind of in the mezzanine between the first and second floors,” she says. “It’s a cool little room. I don’t know why they don’t use it. It is just kind of full of pieces of mirror.”

So, will the Maisels ever sell? Or, more to the point, what’s holding them back? By modest estimates, and even in this economy, the building is worth tens of millions of dollars (see the estimates, here), and the property is so prime that sometimes Linda does reconnaissance before she takes out the trash for fear she’ll have to fend off yet another aggressive agent. “One man called me a bitch because I told him the building wasn’t for sale,” she says.

The Maisels are thinking of renting out the first floor, with its polished wooden floors and basketball hoop over the front door (for more information, e-mail info@190thebowery.com). But leaving?

“I fantasize about never having to worry about money again,” Maisel muses. “It would be great to take the money and run. But let’s face it, where are we going to go? A three-room apartment?”

It cost $102,000 in 1966 …

How much is 190 Bowery worth now?

Maisel won’t let real-estate agents walk through or even see floor plans, so there’s lots of guessing in these assessments. He says his house is 35,000 square feet, 38,000 if you include the exterior walls; propertyshark .com has it at 27,414. Our brokers used various figures in that range. Whatever the size, if Maisel sold the place today, he’d make a hell of an ROI.

Reid Price

Brown Harris Stevens

“Propertyshark.com lists the square footage as 27,500, in which case it’s worth $30 million to $35 million. If it’s [Maisel’s figure of] 38,000, it would be $35, $45 million.”

Erin Boisson Aries

Brown Harris Stevens

“That building is a dream!” she says, putting it at about $45 million to $50 million. “I could see a hip art collector there.”

Peter McCuen

Peter McCuen & Associates

“It’s a tough one, but it might sell for $35 million to a developer or $40 million to a commercial user. Or, in the best scenario, up to $50 million for a high-net-worth buyer for a single-family residence.”

Robby Browne

The Corcoran Group

“Without actually seeing it, I’m guessing the value is between $40 million and $70 million.”

Leonard Steinberg

Prudential Douglas Elliman

Steinberg puts it at $40 million, based on 35,000 square feet, and adds, “I would do anything to get that building.”

Three people live in this building. It was bought in 1966 for $102,000. Now real-estate brokers estimate it’s worth at least $30 million. Photo: Leigh Davis

Amanda’s Bedroom

Maisel built the platforms so his daughter can look at the skyline while lying in bed. Photo: Leigh Davis

The Dining Room

The bankers had their meals here. It’s at one end of the open living room. The pressed-tin wall is original. Photo: Leigh Davis

The Kitchen

The Maisel kitchen is on the site of the bank’s original kitchen, where staff cooked for the bankers. Photo: Leigh Davis

The Kitchen Photo: Leigh Davis

The Maisels on the Roof

Linda has a small garden in one corner; this year, she grew tomatoes, basil, peppers, and parsley. The building’s copper trim is still intact. Photo: Leigh Davis

The Fifth Floor

The plastic tubing runs along the ceiling and carries cold air. Part of Maisel’s collection of curiosities lines the hallway. Photo: Leigh Davis

The Elevator

Maisel used mirrors to enclose the original copper elevator cage for safety. Photo: Leigh Davis

The Third Floor

Once bank offices, now gallery space. The original door frames are oak. Photo: Leigh Davis

Maisel stores his work in the original safe-deposit vault. Photo: Leigh Davis