For those of us who didn't live through it, it can be difficult to imagine what America was like in 1963 -- before civil rights and voting rights, when racial segregation reigned in many places, by law and by custom.
Wednesday's 50th anniversary of the March on Washington -- commemorating one of the most important days in our history -- is an occasion for all of us to reflect on the progress since Martin Luther King Jr. delivered his iconic "I Have a Dream Speech" -- and what is yet unfulfilled.
President Barack Obama made that clear, joining other speakers to emphasize the hard and necessary work still to do in realizing that elusive dream.
Speaking from the same steps of the Lincoln Memorial where King spoke, the president honored civil rights leaders such as King and Rep. John Lewis, a genuine hero.
But, properly and importantly, he mostly paid tribute to "ordinary people whose names never appeared in the history books," who had the courage to risk jail, beatings and worse while steadfastly staying nonviolent.
"Because they marched, America became more free and more fair," Obama said, not just for African-Americans, but for women, gays and all those striving for equality. "America changed for you and for me."
The president then challenged ordinary Americans of today to continue marching in their own ways to change the country for the better.
"I know the road will be long, but I know we can get there," he told the crowd in Washington, D.C. "Yes, we will stumble, but I know we'll get back up. That's how a movement happens. That's how history bends."
While wisely steering clear of any specific policy agenda, he pointed out that those who marched a half-century ago were seeking economic opportunity as well as social justice.
He took a political risk by calling out the politicians and "entrenched interests" who block measures to reduce poverty and growing inequality in America. But he's right.
"Freedom is not given," he said. "It must be won through struggle and discipline, persistence and faith."
Every so often, we need to be reminded of that truth.