On June 19, 1865, Union Army Maj. Gen. Gordon Granger stood on a balcony in Galveston, Texas, and read the Emancipation Proclamation to slaves who were unaware of its original issuance by President Abraham Lincoln two years before.

On June 15, 2015, the nation celebrated the 150th anniversary of that day, known as Juneteenth, when 250,000 slaves were freed and the institution of American slavery dismantled forever.

“A century and a half later, Americans still recognize this occasion, Juneteenth, as a symbolic milestone on our journey toward a more perfect union,” President Obama said in a statement. “At churches and in parks, lined up for parades and gathered around the barbecue pit, communities come together and celebrate the enduring promise of our country: that all of us are created equal.”

U.S. Sen. Benjamin Cardin, D-Md., cosponsored a resolution, S.Res. 201, which was approved unanimously by the Senate and recognizes the significance of this sesquicentennial.

“On this 150th Anniversary of Juneteenth, we gather to observe the end of a painful era in our history. We remember and celebrate the awesome sacrifices that so many Americans made to help bring about the end of slavery…. Juneteenth should serve as an annual reminder that in the United States, freedom has never been free, nor has it ever come easily,” he said.  S.Res. 201 specifically recognize the contributions of Frederick Douglass, a former Maryland slave who became an iconic abolitionist and orator.

“Whether you’re celebrating Juneteenth at a community event or with family and friends, it is important for us to reflect upon how far we have come and the people who made it possible,” said Republican National Committee Co-Chairman Sharon Day in a statement. “Our past is a reminder of the necessity of fighting for equal opportunity and valuing our nation’s efforts to ensure freedom for all Americans.”

Many people said Juneteenth presents an opportunity to reflect on what still needs to be done to fulfill the inherent values on which the nation was built.

“History serves as a blueprint from which we learn, and we recognize that our country has made great strides in race and freedom.  But, still much work remains,” said Rep. G. K. Butterfield, D-N.C., chairman of the Congressional Black Caucus, in a statement. “It is just as important today as it was 150 years ago that we continue our work to ensure all Americans are treated fairly and equitably under the law and each have an opportunity to achieve the American dream.”

“Today is a day for reflection and remembrance,” added Washington, D.C. Mayor Muriel Bowser in a statement. “We have come a long way since the first Juneteenth, but we as a nation must remain vigilant as we continue to build an even brighter future for everyone.”

This year’s Juneteenth celebration was marred by sorrow, however, as the nation still mourns the massacre at Mother Emanuel AME Church in Charleston, S.C. The incident, President Obama said, emphasizes just how much progress needs to be achieved.

“We don’t have to look far to see that racism and bigotry, hate and intolerance, are still all too alive in our world,” he said. “Just as the slaves of Galveston knew that emancipation is only the first step toward true freedom, just as those who crossed the Edmund Pettus Bridge 50 years ago knew their march was far from finished, our work remains undone.  For as long as people still hate each other for nothing more than the color of their skin – and so long as it remains far too easy for dangerous people to get their hands on a gun – we cannot honestly say that our country is living up to its highest ideals.

“But Juneteenth has never been a celebration of victory, or an acceptance of the way things are,” Obama added. “Instead, it’s a celebration of progress. It’s an affirmation that despite the most painful parts of our history, things do get better. America can change.”