(FORTUNE Small Business) – For years Dallas has been known more for barbecue and the Cowboys than for fine arts. But as the city's image shifts upscale, Raymond Nasher deserves some of the credit. A successful real estate developer and art collector, Nasher recently founded the $70 million Nasher Sculpture Center, a 55,000-square-foot museum that displays works from his private collection. "It's one of the most important collections of mainstream modern sculpture," says Robert Storr, professor of art history at New York University and former curator at New York City's Museum of Modern Art. "There's nothing else like this one."

Nasher and his late wife, Patsy, began collecting art in the 1960s, and in the following decades they amassed works by Matisse, Picasso, and Rodin, as well as by contemporary artists, including Richard Serra and James Turrell. "A piece of sculpture, if it is well done, is almost like 360 different pieces if you walk around it," Nasher says. For years he kept most of the collection at his Dallas home, lending some pieces to museums and displaying large sculptures at the NorthPark Center, the flagship shopping mall managed by his real estate firm, Nasher Co. (At 83, Nasher still runs the firm and is currently planning a 400,000-square-foot expansion for the mall. "I don't believe in retirement," he says.)

When his collection became large enough to attract notice, several museums, including the National Gallery in Washington, D.C., the Guggenheim Museum in New York City, and London's Tate Gallery, looked into housing and displaying it. But in 1997, Nasher decided otherwise. "We felt it was our opportunity to give back to our area and make it an international landmark," he says.

The nonprofit gallery, fully financed by Nasher, was designed by Renzo Piano, one of the architects of the Georges Pompidou Center in Paris and winner of the 1998 Pritzker award, the highest honor in architecture. In October 2003 five slender, transparent, connected pavilions opened to display 70 of Nasher's sculptures to the public. A garden holds another 24, among them Richard Serra's massive tilted steel arcs, weighing more than 100,000 pounds. So far the museum has attracted 170,000 visitors. Nasher hopes that they will increase to 250,000 in 2005. With a $5.5 million annual budget and 20 employees, chief curator Steve Nash runs the gallery day to day, but Nasher makes all the big decisions. "He's the one who pulls the trigger," Nash says.

Nasher's philanthropy does not stop in Dallas. Last year he donated $7.5 million to North Carolina's Duke University, from which he graduated in 1943. Duke's new $23 million art museum now has a new name: the Nasher Museum of Art.