Philly is taking center stage for America's 250th birthday

Philadelphia is acting as the "drum major" of the nation's 250th birthday, throwing its biggest-ever party on the Benjamin Franklin Parkway this weekend.

Why it matters: Years in the making, the signature event — paired with a same-day World Cup knockout match — will test even the city that birthed democracy and could define Mayor Cherelle Parker's first term.

The big picture: The "One Philly Unity Concert for America" on the Benjamin Franklin Parkway and the France-Paraguay match in South Philadelphia are both kicking off at 5 p.m., setting up one of the busiest days of the year for city employees.

More than 1 million people are expected to attend the festivities — roughly on par with the 2015 papal visit and last year's Eagles Super Bowl parade.

That means a long night for city workers, who will stay into the early morning to clean up after hundreds of thousands of people leave after the fireworks.

Driving the news: The "legacy" spectacle will reach millions more on television, marking a moment Philadelphians will remember for generations, Parker said during Wednesday's news conference outside the Philadelphia Museum of Art.

Philadelphia is deploying thousands of officers on foot, bikes and horseback, while using drones to monitor crowds, Police Commissioner Kevin Bethel told Axios.

Pennsylvania State Police will send 300 additional troopers, while several of Philadelphia's suburban counties are also providing officers to bolster the city's security presence, Bethel said.

The city has splurged on resources to throw America's biggest Fourth of July party. Photo: Isaac Avilucea

What they're saying: "We only turn 250 years old once," Parker said. "We won't get a second chance to do this over again."

The latest: Road closures are already in place around the Benjamin Franklin Parkway, with more set to take effect as the festivities ramp up.

City officials are urging people to walk, bike or take public transportation to the events.

The city is setting up large cooling tents, water stations and misting fans throughout the Parkway to help people beat the heat, with temperatures expected to top 100 degrees.

Fan Fest will close early Saturday to allow the city to focus more resources on the Parkway.

🧢 1 cool thing: Philadelphia police are even relaxing their dress code to help officers beat the heat, allowing them to wear baseball caps with the department's markings instead of the traditional service caps for the first time, Bethel told Axios.

Zoom in: To prepare for its closeup, Philadelphia moved the main stage — embossed with a giant Liberty Bell — from Eakins Oval to the iconic Art Museum steps.

Comedian Wanda Sykes is emceeing the event, which includes everyone from hometown icons Will Smith, The Roots and Meek Mill to pop star Christina Aguilera and country singer Jordan Davis.

For those who can't make it, the performances will air live on NBC10.

By the numbers: Philadelphia has committed $120 million to citywide semiquincentennial programming — a big but necessary investment intended to show the world the city doesn't lack "ambition," Parker said.

Catch up quick: Unlike the bicentennial, Philly couldn't build a bridge or a museum to mark the occasion, Parker said.

But she says planning for the nation's 250th birthday celebration started the day she was sworn in as Philadelphia's 100th — and first female — mayor.

The city assembled an all-star team to produce the event — rebranded this year after years under the Wawa banner — and tapped ESM Productions, which had a hand in staging Bad Bunny's Super Bowl halftime show.

The bottom line: Drum roll, please.

"This celebration belongs to all of us," Parker said.