Every few months a gaggle of tourists and history buffs follow Bruce Kayton through narrow cobblestone streets for his "Robber Baron tour" of Wall Street, making stops where the Rockefellers extended their empire and Standard Oil dispatched orders to bust unions. Then his Radical Walking Tours comes to the foot of a towering modern building at the edge of Wall Street.

At this point Kayton smiles.

"Here are people doing things for the good of the city, country and humanity," the native New Yorker says in his heavy Brooklyn accent. "A progressive site, an innocent enclave of morality amidst the corruption and rat race of the rest of Wall Street."

Inside the tower, and nestled away in many office warrens throughout the Financial District, thousands of folks labor for left-leaning think tanks, gay rights groups, programs for battered women, arts collectives and AIDS-related causes.

Once an anomalous presence in the gilded corridors of capitalism, these nonprofits have been lured here by cheap real estate, accessible transportation and the fundraising potential that comes with living cheek by jowl with some of the city's deepest pockets.

The changing cultural landscape has given a new purpose to the southern tip of Manhattan. Flickers of life now appear after dark in neighborhoods that once emptied after working hours. Businesses have found new investment opportunities among their new neighbors, and the nonprofits have infused a wounded area with a cultural life and potential for growth.

About 50 cultural groups now claim the Financial District as their home, as an estimated 2,000 visual artists work in Lower Manhattan in addition to the advocacy groups championing myriad political and social issues.

"Nonprofits have been really the only dependable source of new lease office space," said Jonathan Bowles, a fellow at the Center for an Urban Future, a development think tank on Wall Street. "It's really helped diversify the area."

The nonprofit move downtown took root in the early 1990s. A recessionary storm was howling, financial firms were fleeing, and the vacancy rate hit 30 percent in Lower Manhattan. Elsewhere in the city, rising real estate prices had priced out nonprofits. City officials worried about job losses in one of the economy's largest sectors brokered deals and offered tax incentives to help the groups relocate downtown. (Many of the older financial buildings also no longer met the needs of modern investment firms.)

In the summer of 1998, the left-liberal radio network Pacifica Radio planted the flag of its local affiliate -- WBAI -- in Wall Street. "The voice of the people is broadcasting from the belly of the beast," radio host Amy Goodman half-joked on the station's inaugural day.

It proved more congenial than the lefty broadcasters might have imagined. There were quite a few pin-striped suits, but rents were half those in Harlem and many of the activists who made regular appearances on the community radio station were nearby.

"I thought it was a great idea to be around people who were working for social change," said Pat Scott, Pacifica's former executive director. "My biggest issue was it was nice, it was central and it had inexpensive rent."

Rents in Lower Manhattan average $33 a square foot, compared with $45 for Midtown spaces, according to recent figures from the New York City comptroller's office. In the heart of the financial world, nonprofits have found rentals at $26 per square foot and lower, generally considered the magic number for attracting a low-budget outfit.

The movements of nonprofits downtown accelerated after the Sept. 11, 2001, terrorist attacks. Again, the bottom fell out of the real estate market and nonprofits have rushed into the void, renting spacious lofts, vacant offices and abandoned industrial sites and generally settling into one of the most prestigious Zip codes in town.

"It's only the beginning," said Suzanne Sunshine, director of the nonprofit division for the real estate company Cushman & Wakefield. "Not-for-profits have an intuitive sense for new frontiers -- that's what's happening in Lower Manhattan."

Being pioneers means that these groups are not moving into well-established bohemian enclaves such as the Lower East Side or the East Village.

Sure, for a mere $18 a square foot, a shoestring cultural group such as Alwan for the Arts can find a fourth-floor loft near the statue of the stock market bull. But come dusk, while cocktail sippers and diners spill onto the sidewalks in nearby neighborhoods, the Financial District transforms into a ghost town.

The Arabic poetry readings and Persian classes at Alwan become one of the few after-hours venues in the neighborhood. With less competition than in other areas, the Financial District's arts groups draw a crowd eager for entertainment close to the office.

"It's not exactly that we're alone," said Alex Khalil, the 40-year-old unofficial leader of the collective. "We see it as an opportunity for people who work in the neighborhood to walk over and attend an event."

The goal is to provide a venue for developing artists, Khalil said. And, he added in an aside about the neighborhood's prevailing capitalist view, "no one wants to make a penny."

In early June, the movement downtown took a new form, as heavyweights from the city's political and art circles celebrated the arrival of high culture in Lower Manhattan. The Lower Manhattan Development Corp., a joint city-state agency charged with overseeing the rebuilding of Ground Zero, selected four arts organizations as tenants of the future World Trade Center site. The groups will receive a multimillion-dollar subsidy to set up shop downtown.

Among the winners was the Freedom Center, a museum with a focus on the "quest for freedom" proposed by Tom Bernstein, a former partner of the Texas Rangers with George W. Bush. Other selected cultural institutions included the Joyce International Dance Theater, Signature Center and the Drawing Center.

Mayor Michael R. Bloomberg (R) heralded the dawn of a "cultural renaissance," saying that "the World Trade Center site will be getting four dynamic institutions that reflect the excitement and diversity of New York City, and will energize the surrounding community, culturally and economically."

But some fear that the arrival of these big groups, and the related effort to lure back financial firms, will crowd out the hundreds of smaller pioneers. City Council member Alan Gerson (D), whose district includes parts of Lower Manhattan, worries that as rents rebound, the cultural groups and nonprofits that lack political connections and hefty endowments will get chased out.

This has tended to be the nature of things in New York, as nonprofits move nomad-like from one up-and-coming neighborhood to another. Gerson has proposed that rebuilding plans for Lower Manhattan include a strategy for insulating shoestring budget groups with subsidies. "The future of the Financial District is a significant cultural presence," he said. "That will only happen if we make a conscious effort to diversifying the cultural development throughout Lower Manhattan."

That said, some groups prosper because of their proximity to the wealthy. Once Kevin Cunningham and his experimental art group, 3-Legged Dog, were located in 7 World Trade Center, but the building collapsed in the Sept. 11 terrorist attacks. Now he wants to return to Lower Manhattan because of the rewards that come with having rich Wall Streeters as neighbors.

His company fosters collaborations between artists and software developers to create new technology used in visual art. Down here, he says, they find many investors to help turn their innovations into business opportunities.

"We started interacting with business people here and the company started to blossom," he said, "that wouldn't have happened in the East Village."

At the entrance of his new vast empty warehouse, one block from the New York Stock Exchange, Cunningham talks of his plans for constructing large-scale multimedia installations using computers and wide open spaces. Take away the flashing lights and the cutting-edge technology, he says, and what a New York City artist really needs is space. "It means the same thing," he said, "as having a home."

Alex Khalil, left, director of Alwan for the Arts in Lower Manhattan, says the goal is to provide a venue for developing artists.An early-1990s recession and the 2001 attacks caused some firms to flee, making space on Beaver Street available at low rents to nonprofits.Photographer Q. Sakamaki presents a slide show of portraits of Palestinians at Alwan for the Arts, which leases a fourth-floor loft in the Financial District.