DALLAS (AP) — As people gather across the U.S. to celebrate Juneteenth on Friday, former President Barack Obama's presidential center will open its doors to the public for the first time.

Located on a sprawling campus on Chicago's South Side, the center for the nation's first Black president has been designed to inspire people to make the change they want to see in their own communities. It's the kind of contemplation that also comes as Americans gather for Juneteenth, which celebrates the end of slavery in the U.S.

READ MORE: A beginner's guide to celebrating Juneteenth

The holiday marks June 19, 1865, when Union troops arrived in Texas at the end of the Civil War with an order declaring the state's enslaved people were free with "absolute equality" 2 1/2 years after the Emancipation Proclamation freed enslaved people in the South.

"Juneteenth represents not just a commemoration of the end of slavery but it's also part of the ongoing struggle for absolute equality and that ideal in American life," said W. Caleb McDaniel, a Rice University professor and author of the Pulitzer Prize-winning book "Sweet Taste of Liberty."

Obama's presidential center in Chicago

Several days of events have been planned for the grand opening of the Obama Presidential Center, including a dedication ceremony held Thursday.

The center's public opening also arrives as a symbolic convergence of legacy and liberation. The nation is grappling with deepening political division and renewed questions about the arc of racial progress as the Supreme Court hollowed out the Voting Rights Act, endangering Black political representation in Congress.

The nearly 20-acre (8-hectare) campus includes a museum featuring a life-sized replica of the Oval Office, a garden designed by former first lady Michelle Obama complete with lettuce and strawberry plants, a professional-grade basketball court, a picnic area with grills and a new branch of the Chicago Public Library.

In addition to spaces designed to bring people together, the campus that's expected to draw as many as 1 million visitors annually aims to also encourage personal reflection. Louise Bernard, the museum's director, has said they're "inviting people to bring change home, however change may be defined, both small or large."

The museum lets visitors experience high-tech and hands-on exhibits spanning the campaigns, key moments of Obama's presidency and life at the White House.

The history of Juneteenth

This is the fifth year since Juneteenth was designated as a federal holiday by former President Joe Biden, who served as Obama's vice president. But the celebrations, which began in Texas and then spread across the country, have a rich and long history in Black America, with the day often spent gathering for picnics and cookouts.

The holiday — a combination of "June" and "nineteenth" — marks the day that U.S. Maj. Gen. Gordon Granger and his troops arrived in the Texas port city of Galveston with the declaration of freedom in General Order No. 3.

As the third year of the Civil War neared, President Abraham Lincoln had issued the Emancipation Proclamation declaring the freedom of "all persons held as slaves" in the still rebellious states of the Confederacy. Though, for many, it did not mean immediate freedom but a promise of freedom with a Union victory.

"It really required the force of arms and the success of U.S. armies to enforce the Emancipation Proclamation," McDaniel said.

About six months after Granger's arrival in Galveston, the 13th Amendment abolishing slavery was ratified.

Celebrations across the nation

Galveston, the birthplace of Juneteenth, is celebrating with a daylong gathering at a park with music and fireworks, a parade and a worship service in a historic Black church. In nearby Houston, there will be a lineup of musical artists and a domino tournament at Emancipation Park, established in 1872 by a group of formerly enslaved men.

Other events across the U.S. over the long weekend include a parade in Atlanta, a bike ride in Los Angeles and a festival on Martha's Vineyard.

Several cities across the U.S. will host walks named for Opal Lee, the Texas woman who pushed for years to make Juneteenth a federal holiday. Participants will walk 2 1/2 miles to symbolize the 2 1/2 years it took for the Emancipation Proclamation to be enforced in Texas. Lee, known as the "grandmother of Juneteenth," turns 100 this year.

A holiday for reflection
Black Texans embraced the date of Granger's arrival as one to celebrate, and by the 1880s, "it was difficult to find a significant community in Texas where it wasn't being marked by African Americans," McDaniel said.

"They made it a community celebration, they made it a celebration of not only freedom but also a demonstration of community empowerment and institution-building," he added.

Corey D. B. Walker, dean of Wake Forest University's divinity school, said the holiday offers a way to recognize the nation's "complex history" and what it means to be a U.S. citizen, especially amid efforts by President Donald Trump's administration to undermine the retelling of Black history.

"I think it really reminds people the importance of understanding a fuller, more robust portrait of our nation's history and the many contributions of many individuals who have contributed to America's experiment with democracy," Walker said.