On this day in 1965, the nation watched as peaceful civil rights demonstrators were savagely beaten by police as they crossed the Edmund Pettus Bridge in Selma, Ala., a bloody sacrifice that historians credit with helping to usher in the passage of the landmark Voting Rights Act days later.

Fifty years later, with the nation embroiled in a fresh debate about race in America, the country’s first black president joined a bipartisan congressional delegation and tens of thousands of marchers at the foot of the iconic civil rights landmark to commemorate a day that forever altered the landscape of American history.

“There are places, and moments in America where this nation’s destiny has been decided,”  President Obama told the sea of people who had stood for hours to hear him pay tribute to the day known as Bloody Sunday. “Many are sites of war – Concord and Lexington, Appomattox and Gettysburg.  Others are sites that symbolize the daring of America’s character – Independence Hall and Seneca Falls, Kitty Hawk and Cape Canaveral.”

“Selma is such a place,” he added.

The Rev. James Reeb, a former minister at All Souls Church Unitarian, died in the days before the third march from Selma to Montgomery, Ala. Fifty years later, the church reflects on how he affected the fight for civil rights and how they plan to continue the mission. (Jorge Ribas/The Washington Post)

The speech came several days after the Justice Department released a searing report admonishing police in Ferguson, Mo., for engaging in a vicious pattern of racial bias. The police department was home to Darren Wilson, a white officer whose killing in August of Michael Brown, an unarmed black teenager, sparked nationwide protests about police brutality in communities of color throughout the United States.

From his pulpit in Selma, Obama called the Ferguson report “sadly familiar” and said it highlighted the kind of abuse that gave birth to the civil rights movement decades earlier. But Obama also rejected the notion that the report shows little progress on race has been made over the past half-century.

“What happened in Ferguson may not be unique, ” the president said, “but it’s no longer endemic, or sanctioned by law and custom. And before the civil rights movement, it most surely was.”

“If you think nothing’s changed in the past 50 years, ask somebody who lived through the Selma or Chicago or L.A. of the ’50s,” he continued.  “Ask the female CEO who once might have been assigned to the secretarial pool if nothing’s changed.  Ask your gay friend if it’s easier to be out and proud in America now than it was 30 years ago.  To deny this progress – our progress – would be to rob us of our own agency; our responsibility to do what we can to make America better. “

About 600 people participated in the original march across Edmund Pettus Bridge, which marked the beginning of a planned, 54-mile march to Montgomery, Ala., on March 7, 1965, according to the National Park Service.

Obama was preceded on stage by legendary civil rights figure Rep. John Lewis of Georgia, an Alabama native who was among the marchers seriously injured on the bridge on this date 50 years ago.

Lewis, who had given a tour of Selma to congressional leaders earlier in the day, arrived on stage to a rock star’s welcome before launching into a short speech that called for racial reconciliation and urged listeners to continue the struggle for civil rights.

“We must use this moment to recommit ourselves to do all we can to finish this work,” he said. “There’s still work to be done. Get out here to push and pull until we redeem the soul of America.”

Lewis told the crowd it was an honor to return to his home state and introduce the president of the United States.

“If someone had told me when we were crossing this bridge that one day I would be back here introducing the first African American president, I would’ve said, ‘You’re crazy, you’re out of your mind, you don’t know what you’re talking about,'” he said as the crowd broke into cheers moments before Obama approached the microphone.

Standing before Lewis and Obama, organizers estimate, was a crowd of as many as 40,000 marchers, who arrived early Saturday and were met with bright skies and crisp temperatures, according to weather reports.

Minutes later, both men led the crowd across the Edmund Pettus Bridge.

By the end of the march, crowds lingered to take photos on the bridge, bringing a festive energy to a location that that has long been associated with trauma.

Obama’s march across the bridge remained the culminating moment in a momentous day that began early on Saturday. By 7:30 a.m., streets in and around Selma were already gridlocked with traffic, prompting many marchers to abandon their vehicles and begin walking toward downtown, where long lines quickly formed.

Early in the morning, the staging area in front of Edmund Pettus Bridge looked like this:

Several hours later, a large crowd had begun massing in front of the bridge.

President George W. Bush, who signed the reauthorization of the Voting Rights Act in 2006, was on stage as Obama spoke, as were two dozen congressional Republicans, according to news reports.

Asked if he was disappointed that relatively few Republicans would be on hand for the event, Lewis said, “No, we continue to work and continue to build. We cannot become disappointed,” according to CNN. “We will not give up on anyone.”

After initially signaling they would not be traveling to Selma, several congressional Republican leaders did make appearances in town. Sen. Tim Scott (R-S.C.) was in attendance, and House Majority Leader Kevin McCarthy (R-Calif) was also spotted.

House Speaker John Boehner of Ohio released a statement ahead of Saturday’s speeches.

“Today, 50 years after the Selma to Montgomery marches began, the House honors the brave foot soldiers who risked their lives to secure the blessings of liberty for all Americans.  The harrowing images of that day — the unspeakable violence perpetrated against those who marched — summoned us to live up to our founding principles,” Boehner said.

During the flight to Alabama aboard Air Force One, Obama signed a bill awarding congressional gold medals to those who participated in three civil rights marches that took place in 1965, including Bloody Sunday.

While Saturday’s bipartisan delegation to Selma is unprecedented in size, it is part of a tradition that dates back nearly two decades. In the 50 years since Lewis helped lead marchers on their first effort to cross Edmund Pettus Bridge, he has missed just one commemoration of Bloody Sunday, in the late 1960s. In 1997, he was leaving a bipartisan retreat of House members when he explained to a handful of attendees — including Doug Tanner, the executive director of the nonpartisan Faith and Politics Institute, who was facilitating the event — that he had to leave for Alabama.

A small group of members — about 10 of them — decided to join him the following year. They flew commercial, then traveled on a single bus, and as Tanner recalled of the trip in an interview, “It kind of blew of us away.”

In 1999, twice as many members came.

This Saturday, at least 95 House and Senate members were expected to make the Faith and Politics trip, including 71 Democrats, 23 Republicans and one independent. They didn’t have enough seats on their chartered plane, and they rented seven buses.

“It’s going to be different, but it’s a good problem to have,” Lewis said in an interview.

Among the attendees were the mother and father of Michael Brown. Also attending were the Revs. Jesse L. Jackson and Al Sharpton.

While Obama will be in and out of the state in a single day, the lawmakers will spend three days touring some of the best-known landmarks of the civil rights movement. They will visit Birmingham, where four young girls were killed in a bombing at the 16th Street Baptist Church; Selma’s Brown Chapel, where they will meet with veterans of the movement; and the state capitol in Montgomery, where they will meet with the Alabama Gov. Robert Bentley (R).

“We’re not going to put some kind of lobbying on members. We just want them to feel and be moved when they walk through the 16th Street Church in Birmingham, when the four little girls were killed, when they walk through the part where Bull Connor used the dogs and fire hoses,” Lewis said, adding that he hopes the experience might help facilitate the reauthorization of the Voting Rights Act. “And when they walk across the bridge, maybe they will be moved, and think when we get back to Washington we should take a look, Democrats and Republicans.”

While that seems unlikely given GOP opposition to the measure, the journey is different from other congressional trips. Lawmakers often take a family member along: Sen. Sherrod Brown (D-Ohio) took his two daughters 15 years ago and his mother, a Georgia native, the following year. Then-Majority Leader Eric Cantor (R-Va.) took his son before stepping down last year.

Robert Raben, a Democratic consultant who has gone on the trip multiple times, calls it “a refracted experience” where politicians are forced to see their own actions in the eyes of their family members.

For some, the trip is transformational. Rep. Spencer Bachus, a conservative Alabama Republican who retired from the House last year, joined Lewis and other members several times as they made stops in his native city of Birmingham. Six years ago, Bachus was the only white member to travel with Lewis and other lawmakers to commemorate the 50th anniversary of the Rev. Martin Luther King’s journey to India.

“The United States and our white citizens are the beneficiaries of the nonviolent movement. It saved the United States from going down a very long, rocky bitter division,” Bachus said in a phone interview.

Bachus came to Washington this week to push for criminal justice reform; he credits Lewis with the fact that he was one of a handful of Republicans who signed onto a bill during the last Congress reauthorizing the Voting Rights Act.

“If more of us were aware of the history of the civil rights movement and how sacred the right to vote was to a population that was not allowed to vote, I believe we’d be more sensitive to their concerns,” he said.

(This post has been updated)