Julia Christensen's hometown of Bardstown, Ky. -- "Bourbon Capital of the World," population just over 11,000 -- has a historic Main Street and about 300 buildings on the National Register of Historic Places, including Federal Hill, the mansion thought to be the inspiration for Stephen Foster's "My Old Kentucky Home."

It also had two empty big-box buildings that Wal-Mart had outgrown, shifting the town's center of economic development with each move. A flea market settled into the first one, but eventually the building began to fall apart and was razed. A new county courthouse was built on the site, replacing the regal French Romanesque one that still stands in the center of town. The second Wal-Mart building remains empty.

"That piqued my interest," said Christensen, a new-media artist who, since the spring of 2004, has logged 75,000 miles visiting more than 50 communities that are transforming former Wal-Mart, Kmart and Target buildings into churches, schools, libraries and other community or civic uses. Documenting the renovations with photographs and interviews and collecting field recordings along the way, Christensen uses the material in video-sound installations and in lectures to communities about the reuse of big-box buildings.

Her exhibit, "Your Town, Inc.," opened last week at Carnegie Mellon University's Regina Gouger Miller Gallery. It's the first show curated by the gallery's new director, Astria Suparak, who was attracted to what she describes as the "critical but optimistic" stance of Christensen's work.

"By looking at what people are doing with these spaces," Christensen said, "we can see how resourceful and creative communities can be and also what a huge challenge this is for communities across America.

"The buildings are so big that it is often hard to find a user that needs so much space. That's the first major challenge. And they are created with a single purpose in mind -- one-stop-shopping retail. Breaking up the space becomes difficult."

But their locations, it turns out, are a plus, and usually cited as the main reason the new owners were attracted to the buildings, which early on benefited from infrastructure improvements such as widened roads and new traffic signals. And there is, of course, plenty of parking.

Both the exhibit and Christensen's book, "Big Box Reuse," due in November from MIT Press, feature 10 adaptive reuse projects, including the 2001 conversion of a Kmart into the 16,500-square-foot Spam Museum in Austin, Minn., where the mystery meat is produced. The museum's playful attitude comes through in the lively but traditional checkerboard-patterned facade by Paulsen Architects, which helps attract about 100,000 visitors a year.

Breaking down large, featureless buildings into structures that are more human-scale and inviting is another challenge. In Wisconsin Rapids, Wis., the community was against putting a senior resource center into a former Wal-Mart.

"Part of the challenge for the architects -- Vierbicher Associates, based in Madison -- was getting the community to buy into this by making it not look like a Wal-Mart," Christensen said. "They tore down several thousand square feet on one side of the building and replaced it with green space. They varied the facade to give it texture, and built awnings and walkways that jutted out from the building so it wasn't just a single flat plane. And they greened up the parking lot with trees and created walking paths that integrated with the downtown walking path, so it was more friendly to pedestrians."

Along with 78 photographs of big-box transformations, "Your Town, Inc." includes the UnBox, a sculpture Christensen built with students at Oberlin College, where she is the Henry R. Luce Visiting Assistant Professor of the Emerging Arts.

"I wanted to build something opposite," said Christensen. "A big box usually can't easily be moved, isn't made of anything recycled or recyclable, or made of anything local. With the UnBox building I decided to make something that was modular, transportable, made of local materials and had multiple uses. We never set foot in a big-box building to build the whole thing," relying instead on the local hardware and five and dime stores. "We drove it over here on a truck running on vegetable oil discarded from our local restaurants."

Christensen said the UnBox, which looks like a large, deconstructed box, will be the setting for group discussions about issues raised by the exhibit.

At Oberlin, Christensen has a joint appointment in two departments: Studio Arts, and Technology in Music and Related Arts.

"I'm a varied sound artist," said Christensen, who grew up playing the piano and now plays mandolin and guitar. "I have some bluegrass in my bones but also have an MFA in electronic music."

On her big-box trips she gathers sound; one of her pieces, "Rust Belt/Bayou," explores the similarities between Cleveland and New Orleans. It's available on her Web sites, www.bigboxreuse.com and www.juliachristensen.com.

Christensen will be back in town for an exhibit reception and barbecue (free to all) from 6 to 8 p.m. Sept. 19 and again on Nov. 13, when she will give a gallery talk and sign her book from 4:30 to 6 p.m.

Her work also is included in "Worlds Away: New Suburban Landscapes," opening Oct. 4 at Carnegie Museum of Art's Heinz Architectural Center.