Twenty-five years ago, you wouldn't have spent a Friday or Saturday along the seedy Downtown corridors of Penn or Liberty avenues unless you were in the market for "adult" entertainment, "marital aids," paid companionship or porn.

Today those same streets are the heart of the Cultural District, drawing 1.5 million patrons last year to the symphony, ballet, opera, theater, galleries and restaurants.

The Pittsburgh Cultural Trust has been the driving force in this transformation, and it's celebrating its 25th anniversary this weekend with a two-day party for the public to showcase the district and all that it offers.

The metamorphosis came about because H.J. "Jack" Heinz II envisioned a cultural district in the heart of Downtown that would act as an engine for economic development. He and other city leaders mapped out an area where an arts district would do the most good, bought up "noxious" properties for conversion and established the Pittsburgh Cultural Trust to make it happen.

Today that area of town boasts Heinz Hall, the Benedum Center for the Performing Arts, the O'Reilly Theater, Theater Square, the Harris Theater, Katz Plaza, Wood Street Galleries, SPACE, loft apartments and the Allegheny Riverfront Park, as well as numerous smaller arts spaces, offices, art works and restaurants.

The Trust not only created most of those venues (Heinz Hall preceded the Trust), it acts as presenter for national and international events. It also has commissioned art and rescued several arts groups whose futures were imperiled.

Not everything has gone smoothly. Rocky labor negotiations in the Benedum's early years almost canceled a run of "Phantom of the Opera." The Theater Square project took much longer to complete than expected. Last year, citing the national financial crisis, the Trust suspended its most ambitious plan to date, the $460 million RiverParc housing development on Fort Duquesne Boulevard. That prompted a breach of promise lawsuit by the former developers. And this year the bad economy prompted the layoff off 10 employees and an 18 percent cut in the programming budget.

Nevertheless, many would say the Trust has exceeded expectations. Attendance at district events has more than quadrupled from 347,000 in 1987, the year the Benedum opened. Meanwhile, the Trust's operating budget has soared from $169,000 in 1984 to $52 million this year.

There's also been a lot of private development that may not have happened if the Trust hasn't jump-started the clean-up. These include several new hotels, four high-end condo developments and three more moderately priced projects with lofts and apartments.

"The original vision from Jack Heinz to use the arts as an incentive to attract new investment in Downtown has been phenomenally successful," said Carol Brown, who served as its first president from 1986 to 2001.

"There's no question it has become a role model of using the arts for Downtown development and for helping the arts themselves to mature. People have come from other parts of the country and Europe to see what was done here and how it was done."

How it was done was slowly and methodically, with lots of foundation money up front leveraging investments from the public and corporate sectors. The Trust plowed income from its properties back into the District, and sometimes it sat on land for a long time until the right project came along.

Janet Sarbaugh, director of the Arts and Culture Program at the Heinz Endowments, noted how closely the Trust has hewed to Mr. Heinz's original vision.

"The major concepts are very much in place," she said. Those include placing high visual art standards at the center of the Trust's work, commissioning work from local and outside artists and emphasizing high-quality architecture and design.

"The idea of making the district a visually beautiful place has migrated to other parts of Downtown," Ms. Sarbaugh added. "Now I do not think of it as an island."

She cited the renovation of Point State Park, the work of the Riverlife Task Force and the expansion of Point Park University as evidence that aesthetic concerns have taken root.

Noting the challenging, if not scary, nature of the current economy, Trust President J. Kevin McMahon said his main goal is keeping the organization solvent.

He's hopeful that when the economic picture improves, the Trust will be able to increase major attractions to supplement local offerings, and to resurrect the RiverParc project that was put on hold.

Meanwhile, he said, the last adult video store on Liberty Avenue is gone. And the August Wilson Center opens soon at the eastern entrance to the District.

"We think the transformation of Penn and Liberty has largely been accomplished. There are still empty storefronts and offices in upper floors we need to address and some facade fronts that need repair."

In a statement, Teresa Heinz, chairman of the Heinz Endowments and the Heinz Family Philanthropies, said the Trust's successes speak for themselves.

"This milestone anniversary should effectively bury the shallow notion that art museums, stage theaters, galleries and concert halls are frills or decorative luxuries in community life," she said. "The arts can be powerful enough to transform seedy and unsafe spaces into vibrant and welcoming spaces."

Added Ms. Brown: "I think Jack Heinz would be very pleased."