Frank Lloyd Wright designed the Zimmerman House in his Usonian style, emphasizing simplicity and efficiency. (Currier Museum of Art)

The air changes from climate-controlled and dry to cool and damp as I peer into a large pipe that extends from a 10-foot-wide hole in the brick wall. Although the centuries-old penstock no longer channels water from canals to turbines to power this former cotton mill, there’s still a shallow puddle at the bottom of the pipe.

I’m in the Millyard Museum in Manchester, N.H., and just beginning to learn about this city that I’ve largely missed in my years living in southern New Hampshire. That’s because the state’s largest city has always been more practical than pretty, losing out to Portsmouth and the White Mountains when it comes to classic New Hampshire beauty and charm. Instead of maple sugar and quaint covered bridges, Manchester had mills. The city grew up around the Merrimack River and Amoskeag Falls, which powered an industrial complex that for more than a century produced textiles for the entire world.

The imposing brick mill buildings on the river aren’t the only unusual architecture in town. The only Frank Lloyd Wright house in New England open to the public is in Manchester, and another of the architect’s houses is just a few doors down from it. There’s also a quirky little art deco airport terminal that’s now home to a museum.

The Millyard Museum is in a small section of one of the old mills, most of which have been revamped into apartments, restaurants and offices. A hundred years ago, though, these buildings were part of the Amoskeag Manufacturing Co.’s “walled city,” where thousands of people, including children, lived and worked. In the museum are huge looms with spools of colorful thread feeding a half-finished piece of cloth, and bins of raw white cotton, the leaves and seeds still attached to the bolls. One display houses a torpedo-like shuttle, like the ones that were automated to fly across the looms to weave the cloth. I push a button and the shuttle drones to life, bouncing back and forth with enormous force. The noise is earsplitting.

“Magnify that sound by a hundred times,” a visitor says to his wife, and I imagine the deafening noise engulfing this cavernous brick room and every room on every floor of every building along the river.

Amoskeag Manufacturing closed in 1935, a victim of the Great Depression and changing times. Two years later, the Works Progress Administration built an art deco terminal for the city’s airport. It was used until 1995, then moved to its current location on the south side of the Manchester airport in 2004.

With its square body, round windows and the glass box atop its roof, the terminal, which now houses the Aviation Museum of New Hampshire, is a little forlorn-looking, plopped at the edge of a parking lot on the airport perimeter. A man is standing outside, taking pictures of a Southwest flight that’s taking off. I ask him if he works at the museum, and he nods.

“Zero percent wages but 100 percent fun, you know what I mean?” says volunteer docent Dave Desilets.

The museum highlights New Hampshire aviation and space luminaries such as Alan Shepard and Christa McAuliffe and a new $1 million learning center that’s just weeks from its grand opening. But the most fascinating part of the visit is talking to the docents, all retired aviators. Richard Fortin tells me that he was in the “spy business,” stationed in Adana, Turkey, as an Air Force electronics intelligence technician who serviced the planes that flew along the border of the former Soviet Union. “And sometimes overflew the Soviet border,” he says.

I mention that my next stop is the Zimmerman House, the Frank Lloyd Wright landmark now owned and operated by the Currier Museum of Art. “My father helped build the Zimmerman House,” says Richard, who was a teenager during its construction in 1950. “It looks like a restroom to me, with all the windows.”

Museum docent Paul Scarlett worked on the house during its restoration in the late 1980s. He tells me that while installing a new radiant heating system, the workers found an envelope containing the names of the original construction crew. He and his co-workers added their own names and put the envelope back where they’d found it. “Now my name is under that floor,” he says.

When I arrive at the Zimmerman House a couple of hours later with a tour group from the Currier Museum, I have to laugh. Richard’s right: It does kind of look like a rest stop, with the plain brick facade, pitched roof and row of small square windows along the roofline. There’s no attic, no garage, no basement; just a small carport and an attached storage shed. Wright designed the house in his Usonian style, emphasizing simplicity and efficiency. We slip blue hospital-style booties over our shoes and walk in.

All comparisons with a restroom end outdoors. We squeeze through an incredibly narrow front hallway, and suddenly the space opens up to reveal a 13-foot pitched ceiling, a wall of mitered-glass windows and furnishings that have been here for more than 60 years.

“What you see is what the Zimmermans lived with until they died,” says our guide, Judith Ransmeier. Local doctor Isadore Zimmerman and his wife, Lucille, commissioned Wright to design not only their home but also the landscaping, the mailbox, the furniture and even their table linens.

There’s only about 1,700 square feet of living space, and everything in the house does double duty as both functional and decorative. The couch and every shelf are built into the walls. The rooms are tiny. Although it’s hard to imagine living here, it’s fascinating to look around, and the craftsmanship is exquisite. The grains of the cypress-wood walls continue as they turn at 90-degree angles. The poured-concrete floors extend out to the patio, creating the illusion that indoors and outdoors are one.

“This house was built as if it was a piece of fine furniture,” Judith says.

Afterward, I ask her whether she has heard about a piece of paper with the workers’ names beneath the floor. She hasn’t, but the Zimmerman House is surrounded by lore, she says.

I, for one, hope that the story’s true. I like the way Manchester seems at once like a big city and a small town, both industrial and rural. Maybe it’s not nestled beneath a mountain or perched near the ocean, but it has a quirky attraction all its own.

Pecci is a freelance writer in Plaistow, N.H.