Fifty years ago, hundreds of civil rights marchers trying to cross the Edmund Pettus bridge in Selma, AL were set upon by police, beaten, clubbed, and tear gassed, sending many to the hospital. That event, known as "Bloody Sunday," was commemorated yesterday by President Obama and thousands of marchers - some of them who took part in the original protest.

ABC News:

While praising the accomplishments of the marchers at Selma and across the country in the civil rights movement, he also reminded his listeners that the work is not finished.

"We just need to open our eyes, and ears, and hearts, to know that this nation's racial history still casts its long shadow upon us," he said. "We know the march is not yet over, the race is not yet won, and that reaching that blessed destination where we are judged, all of us, by the content of our character -- requires admitting as much, facing up to the truth."

Touching on the Justice Department's recent report finding rampant racism on the Ferguson, Mo., police department and a municipal government that used its police force to raise revenue, Obama said those findings were reminiscent of America before the late 1960s.

"The report's narrative was sadly familiar," Obama said. "It evoked the kind of abuse and disregard for citizens that spawned the Civil Rights Movement."

Despite the problems revealed in Ferguson, the president urged anyone listening not to forget the progress that's been made.

"We do a disservice to the cause of justice by intimating that bias and discrimination are immutable, or that racial division is inherent to America. If you think nothing's changed in the past fifty years, ask somebody who lived through the Selma or Chicago or Los Angeles of the 1950s," Obama said.

Obama appeared at the same bridge in Selma, Ala., addressing a crowd gathered there for a day of events marking the 50th anniversary of the Selma to Montgomery marches. He was introduced by John Lewis, the civil rights leader who now serves as a Democratic member of Congress.

"I would've told you you're crazy," Lewis said, if anyone had told him 50 years ago that he would return to Selma to introduce the first African-American president.

There were three marches across that bridge in 1965. But it is the first march that is most remembered because of the violence and bloodshed, broadcast into 60 million American homes on the nightly news. There were other events during the civil rights era that impacted the political debate in Washington over civil rights and voting rights legislation. But perhaps no other event catalyzed the movement and caused ordinary white Americans to back civil rights legislation as the first march in Selma.

Here's one of the president's more eloquent passages he spoke yesterday:

As is true across the landscape of American history, we cannot examine this moment in isolation. The march on Selma was part of a broader campaign that spanned generations; the leaders that day part of a long line of heroes.

We gather here to celebrate them. We gather here to honor the courage of ordinary Americans willing to endure billy clubs and the chastening rod; tear gas and the trampling hoof; men and women who despite the gush of blood and splintered bone would stay true to their North Star and keep marching toward justice.

They did as Scripture instructed: “Rejoice in hope, be patient in tribulation, be constant in prayer.” And in the days to come, they went back again and again. When the trumpet call sounded for more to join, the people came – black and white, young and old, Christian and Jew, waving the American flag and singing the same anthems full of faith and hope. A white newsman, Bill Plante, who covered the marches then and who is with us here today, quipped that the growing number of white people lowered the quality of the singing. To those who marched, though, those old gospel songs must have never sounded so sweet.

In time, their chorus would reach President Johnson. And he would send them protection, echoing their call for the nation and the world to hear:

“We shall overcome.”

What enormous faith these men and women had. Faith in God – but also faith in America.

And courage. The voting rights campaign was carried out largely without the protection of the government, resulting in numerous beatings and murders of activistst. The Tuesday following Bloody Sunday, there was an aborted march across the bridge, halted because of an injunction issued by a federal judge. That night, a white northern preacher was one of four marchers set upon by Klansmen. He died of his injuries a few days later.

It is right and proper that we commemerate this event and remember the sacrifices of those who fought for the simple idea that they were as good as any other American, regardless of their race. To be able to vote, to sit at the same lunch counter with white people, to be able to drink from the same public water fountain as anyone else - these small victories have helped define American exceptionalism and serve as examples of the kind of nation we can be when we stand up for equality and the law.