"It's a great treat to be here with such a fine audience of art lovers and artists," cooed Debbie Harry, surveying the crowd at the Whitney's groundbreaking gala last week. "Downtown people, uptown people, all kinds of New Yorkers."

When Blondie's right, she's right—many of the museum's supporters, arrayed in front of her at tables that cost some $25,000 apiece, were indeed uptown people, Upper East Side people, neighbors of the museum's current location at 75th and Madison. But they were gathered downtown, in a tent surrounded by chain-link fencing and construction paraphernalia on the corner of Washington and Gansevoort—future site of the museum's Renzo Piano building, planned to open in 2015. It was different!

"It might be the most groundbreaking groundbreaking you've ever seen," said Mayor Bloomberg at the dirt ceremony Tuesday. Dancers from the Elizabeth Streb company threw themselves through plate-glass windows as Ms. Streb stood under a cylinder that sprayed sand at her head. In the audience, Renzo Piano wore safety goggles.

The mayor and various trustees then crowded around Ms. Streb to dig at her feet, for photos.

Downtown wasn't the Whitney's first choice. A previous expansion plan had the museum building off its current building at 75th, but it fell through after the Landmarks Commission wanted a change that Mr. Piano said he'd jump in a lake before making.

"I prefer here," Mr. Piano told The Observer after the ceremony Tuesday. "It's more vibrant."

The space at the base of the High Line had been considered by at least one other art institution—the Dia Foundation. For a while, the Whitney's plan was unclear—would it build a downtown annex, or make a wholesale move? After some trustee disagreement, it became clear it would be the latter—it would bet the house on downtown—and now the writing is on the wall in the meatpacking district. Or on the streetlights, anyhow, which have been embellished with fluttering banners announcing, with the mute drama of haiku, the museum's imminent arrival: "The Whitney/Ground Breaking/ The Future."

If ground breaking is in the streets, at the gala it was also in the air—and on the table. Above the diners, and the stage where Blondie performed, hung lines of teal-color shovels. Centerpieces were composed of orange construction tape.

"It makes sense, doesn't it?" Whitney director Adam Weinberg said at the gala. "I still think we'll bring in a lot of people from our East Side base. We're not even way downtown, at the bottom, we're not at the tip of Manhattan. Fourteenth Street is semi-midtown, even."

Translation: downtown, but not too downtown. Close enough that, if you build it, they'll come, even if that means—egads!—public transportation. "Sure I take the subway!" enthused Amy Phelan, Dallas Cowboys cheerleader-turned-contemporary art collector and Whitney donor, at the gala. When in New York, she lives on the U.E.S. 

The Whitney has some $212 million to raise on its $720 million building project—the gala made a $2 million dent, and they nabbed $100 million by selling the uptown townhouses bought for the aborted expansion—but this is not bad news. "They've got four years to show potential donors the building site and, as the building goes up, to show them the cavernous hall that could be named after them," said David Gordon, a former museum director and now consultant to cultural institutions. "There's something to be said for starting construction. The most important thing is to convince the doubters who said, 'It's never going to happen.'"

The cash will come from wealthy benefactors—"I hope they have a Russian oligarch hidden in a closet," one art world source joked—but where will visitors come from downtown? Shoppers at the Alexander McQueen and Stella McCartney boutiques? Diners from Spice Market and Pastis? Artsy swells lodging at the Gansevoort, Soho House and Andre Balazs's Standard Hotel, which has launched its own culture program?