President Barack Obama says America's racial history "still casts its long shadow" despite a half-century of progress toward a more perfect union.
In Selma, Alabama, Mr Obama stood in solidarity and remembrance on Saturday with survivors of a civil rights era that he was too young to know.
He joined civil rights marchers of 50 years ago at the bridge where police brutality on "Bloody Sunday" galvanised America's opposition to racial oppression in the South and hastened passage of historic voting rights for minorities.
Thousands from across the US packed the riverside town for commemorations of the March 7, 1965, march.
Mr Obama said that police discrimination against blacks is not confined to Ferguson, Missouri - but that it's also no longer endemic or sanctioned by law in America.