Standing on hallowed ground of the civil rights movement, President Barack Obama challenged new generations Wednesday to seize the cause of racial equality and honor the "glorious patriots" who marched a half-century ago to the very steps from which the Rev. Martin Luther King Jr. spoke during the March on Washington.
In a moment rich with history and symbolism, tens of thousands of Americans of all backgrounds and colors thronged to the National Mall to join the nation's first black president and civil rights pioneers in marking the 50th anniversary of King's "I Have a Dream" speech. Obama urged each of them to become a modern-day marcher for economic justice and racial harmony.
"The arc of the moral universe may bend toward justice, but it doesn't bend on its own," Obama said, in an allusion to King's own message.
His speech was the culmination of a daylong celebration of King's legacy that began with marchers walking the streets of Washington behind a replica of the transit bus that Rosa Parks once rode when she refused to give up her seat to a white man.
At precisely 3 p.m., members of the King family tolled a bell to echo King's call 50 years earlier to "let freedom ring." It was the same bell that once hung in the 16th Street Baptist Church in Birmingham, Ala., where four black girls were killed when a bomb planted by a white supremacist exploded in 1963.
Georgia Rep. John Lewis, the sole survivor of the main organizers of the 1963 march, recounted the civil rights struggles of his youth and exhorted American to "keep the faith and keep our eyes on the prize."
The throngs assembled in soggy weather at the Lincoln Memorial, where King had pleaded with Americans to come together to stomp out racism and create a land of opportunity for all.
White and black, they came to recall history — and live it.
"My parents did their fair share, and I feel like we have to keep the fight alive," said Frantz Walker, a honey salesman from Baltimore who is black. "This is hands-on history."
Kevin Keefe, a Navy lawyer who is white, said he still tears up when he hears King's speech.
"What happened 50 years ago was huge," he said, adding that there's still progress to be made.
Two former presidents, Bill Clinton and Jimmy Carter, spoke of King's legacy — and of problems still to overcome.
"This march, and that speech, changed America," Clinton declared. "They opened minds, they melted hearts and they moved millions — including a 17-year-old boy watching alone in his home in Arkansas."
Carter listed a string of current events that he said would have spurred King to action in this day, including the proliferation of guns and "stand yourground" laws, a Supreme Court ruling striking down parts of the Voting Rights Act, and high rates of joblessness among blacks.
Oprah Winfrey recalled watching the march as a 9-year-old girl and wishing she could be there to see a young man who "was able to force an entire country to wake up, to look at itself and to eventually change."
Obama used his address to pay tribute to the marchers of 1963 and that era — the maids, laborers, students and more who came from ordinary ranks to engage "on the battlefield of justice" — and he implored Americans not to dismiss what they accomplished.
Civil rights activist Myrlie Evers-Williams, whose husband, Medgar Evers, was murdered in 1963, said that while the country "has certainly taken a turn backwards" on civil rights, she was energized to move ahead and exhorted others to step forward as well.
Performers included Peter Yarrow and Noel Paul Stookey, who also performed at the original march as part of Peter, Paul and Mary. They sang Blowin' in the Wind, as the parents of slain black teenager Trayvon Martin joined them onstage and sang along. The third member of the trio, Mary Travers, died in 2009.
Also joining the events were Lynda Bird Johnson Robb, daughter of Lyndon Johnson, the president who signed the 1964 Civil Rights Act and the 1965 Voting Rights Act, and Caroline Kennedy, daughter of John F. Kennedy.
Former President George W. Bush didn't attend but said in a statement that Obama's presidency is a story that reflects "the promise of America" and "will help us honor the man who inspired millions to redeem that promise." Bush is recovering from a recent heart procedure.
King's eldest son, Martin Luther King III, just 5 when his father spoke at the Mall, spoke of a dream "not yet realized" in full.
"We've got a lot of work to do, but none of us should be any ways tired," he said. "Why? Because we've come much too far from where we started."