Lines were so long getting into the event that some people were waiting all the way back by Logan Square. The security checkpoint was at 22nd Street.
Pennsylvania Senator Bob Casey and Philadelphia Mayor Cherelle Parker kicked off the event.
"We are all gathered here tonight, and 248 years ago to be exact, our democracy was born. Despite what we hear from that other guy, remember, we live in the greatest nation in the world," she told the crowd.
"I want to thank you all for being here and what you're doing for our commonwealth and country at this moment. All the work that's being done, all the doors being knocked on -- it's because of your work. And we appreciate that commitment to our country at this critical time," Casey said.
The event, which was right outside the Philadelphia Museum of Art, was just as much a concert as it was a rally.
People came to see the star-studded lineup, including Lady Gaga, Oprah, The Roots, Jazmine Sullivan, Freeway and Just Blaze, DJ Cassidy, Fat Joe, DJ Jazzy Jeff, Ricky Martin, and Adam Blackstone.
To end the night off, Vice President Kamala Harris took the stage shortly after 11 p.m.
"It's good to be back," Harris told the cheering crowd as she walked on stage.
During her speech, Harris made a final push to get people out to vote on Election Day.
"We have one day to get this done, so now we need to get to work and get out to vote," she said. "We have so much more in common than what separates us. And let us remind everyone -- your vote is your voice, and your voice is your power."
"So tonight I ask you one last time, are you ready to make your voices heard?" she asked the crowd, who responded in cheers. "When we fight, we win!"
This event marked the final push ahead of Election Day for the Harris campaign to make its mark in Pennsylvania, a key battleground state.
City officials told Action News they're prepared to handle what's coming on Election Day, which is Tuesday.
"We have expanded our area of control, we have expanded our staffing over the next couple of days. Some people may be concerned about the event this evening. We have a full staff on location. We've expanded the hours of our men and women. We will be prepared to respond to anything that happens tomorrow and anything that flows from that this week," noted Philadelphia Police Commissioner Kevin Bethel.
Harris and Trump's final push before Election Day brings them to the same patch of Pennsylvania
Vice President Kamala Harris and former President Donald Trump made their final pitches to voters Monday in the same parts of Pennsylvania at roughly the same time, focusing on the state that could make or break their chances during the last full day of the presidential campaign.
In Pittsburgh, Trump delivered what his campaign aides described as his closing argument after his previous attempt - a mass rally at Madison Square Garden in New York -- was derailed by crude and racist jokes. He has also veered off message with falsehoods about voter fraud and invocations of violence.
MORE INFORMATION | Live election 2024 updates in the Philadelphia region and the focus on Pennsylvania
"Over the past four years, Americans have suffered one catastrophic failure, betrayal and humiliation after another," said the Republican nominee, sounding raspy yet energetic after speaking for hours each day.
The crowd exploded in cheers when the Republican nominee said the country should tell Harris, "You're fired," his catchphrase from "The Apprentice," the reality television show that made him a nationally recognized star.
Harris made stops in Scranton, Pittsburgh, and Reading before her rally in Philadelphia Monday night.
With 19 Electoral College votes, Pennsylvania is the biggest prize of any battleground. A Trump victory there would puncture the Democrats' "blue wall" and make it harder for Harris to win the necessary 270 votes.
The Associated Press contributed to this report.