One hundred years after the Founding Fathers signed the Declaration in Independence Hall, Philadelphia threw a crowd-pleasing Centennial Exhibition, which promoted the city's fast-growing factories and put Fairmount Park on the map.

For the 150th, we hosted the Sesquicentennial. The "world's fair" was a bust; but it left us with the city's top modern attraction, the South Philly stadium district. And the Ben Franklin Bridge.

The 1976 Bicentennial brought us All-Star games and the Final Four. The public party was a bust; but the energy that went into clearing Independence Mall for it helped make Center City living fashionable again.

Now, a national group led by Philadelphians has been charged — by Congress and President Trump — with organizing projects to mark 250 years of American independence, in 2026. There's time to plan a big Philly party with a purpose, and maybe to build useful, lasting improvements. If we don't blow it.

It's the "Semiquincentennial," according to the federal law licensing the celebration, signed by President Barack Obama in 2016. (A quincentennial marks 500 years; a semi-quin is half as much.)

"We need a new name. I've been saying 'Two-fiftieth,' " says Dan DiLella, the suburban Philly developer who will chair the United States Semiquincentennial Commission, which holds its first informal meeting, to be convened at Independence Hall, later this week.

The commission will gather more formally this fall, probably at the Union League. Besides DiLella, who was picked for the job by U.S. Senate Republicans, the Philly caucus includes among its 24 voting members infrastructure-finance investor Andrew Hohns, who started the nonprofit USA250 effort back in 2008 to push for the commission legislation and "coordinate, develop, assist, and inspire" state and local efforts; and Comcast consigliere David L. Cohen, both nominated by Senate Democrats. Other locals include Penn president Amy Gutmann, tapped by U.S. House Minority Leader Nancy Pelosi (D., Calif.).

Sen. Pat Toomey (R., Pa.) called DiLella a couple of months ago to offer the chairmanship. DiLella went to breakfast at the White House, and met with Secretary of the Interior Ryan Zinke. President Trump signed the papers, "and I've been trying to contact all the other commissioners and move the thing along," DiLella told me.

As a Philadelphia-area developer, DiLella is smooth at dealing with investors, plans, and planners, all the levels of government. A Villanova trustee and real estate program patron, DiLella also heads the advisory board that has lately expanded Roman Catholic High School with new science, arts, and sports buildings, among his other philanthropies.

DiLella last week tapped Frank Giordano as the commission's executive director. Giordano, heir and boss at Atlantic Trailer Leasing, has applied private-sector marketing and fund-raising savvy to turn around two once-struggling Philly institutions he's headed: the Union League club, now the hub of a regional web of restaurants, golf clubs, parking, networking, and scholarship programs; and the Philly Pops orchestra, with its rejuvenated schedule.

The Semiquin, so far, has "no budget," said Giordano. "You want coffee? That's about all we can afford today." The American Battlefield Trust (formerly Civil War Trust) is helping get the work organized.

We met at the new headquarters of DiLella's company, Equus, which he recently moved from Philadelphia to the Newtown Square development that's now home to SAP, Main Line Health, a new Hilton Garden hotel, new Toll Brothers homes, and other assets whose owners prefer the green country west of town.

That's as if to underline it's not a foregone conclusion that the big celebration will be in Center City. The law urges commemorations, not only in Philadelphia, but in the other colonial ports of Boston, Baltimore, Charleston, S.C., and New York, and across the 13 founding states.

No need to stop there, says DiLella: "It's a celebration of the entire country, with an emphasis on where we are today — one of the most successful countries in the history of the world." Giordano wants a focus on "innovation," the new technologies and developing industries, like the old Centennial. Giordano hopes local committees will go beyond the familiar Revolutionary stories to use the occasion to mark "seminal moments" in American history — 9/11, World War II, Emancipation, the Industrial Revolution. Hohns says professional, religious, service, and patriotic groups are also weighing plans.

So are the states, which are being encouraged to build celebratory structures: Pennsylvania's proposal, working its way through the General Assembly, calls for a commemorative "pavilion" somewhere in the commonwealth.

"Maybe we'll get some development going down on the Delaware," DiLella suggested.

"We don't need to build another stadium. We have three," Giordano pointed out.

Hohns would like some kind of virtual-reality experience, where we could see what key places in America looked and felt like at different points in history.

Giordano has a pet idea that won't cost much: "On July 4, 2026, at some time of the day, wherever you are, everyone should stand up and sing 'God Bless America.' "

What if there's no consensus? What if commission factions, or regions and groups that don't feel part of the process, and folks who don't like where they think the nation is heading eight years from now, come up with very different ideas of how to commemorate independence, and the meaning of America at 250?

"That's OK. Each city and state can have their own thing," said DiLella. "Because you'll have to raise your own money to do it."

Welcome to America!