Longtime activist Al Sharpton, now an MSNBC host, implored young black men to respect women and reminded them that two of the leading figures in the civil rights movement of the 1960s were women.
"Rosa Parks wasn't no ho," he said, "and Fannie Lou Hamer wasn't no bitch."
Speakers frequently mentioned persistent high unemployment among blacks, which is about twice that of white Americans, and the acquittal of George Zimmerman for the shooting death of unarmed black teenager Trayvon Martin in Florida. Along the Mall, Martin's picture was nearly as ubiquitous as King's.
Nancy Norman of Seattle said she was disappointed more people who look like her had not attended -- she is white -- but the 58-year-old said she was glad to hear climate change discussed alongside voting rights.
"I'm the kind of person who thinks all of those things are interconnected. Climate change is at the top of my list," Norman said. "I don't think it's one we can set aside for any other discussion."
Those in attendance arrived in a post-9/11 Washington that was very different from the one civil rights leaders visited in 1963.
Then, people crowded the steps of the Lincoln Memorial and could get close to King to hear his "I Have a Dream" speech. Saturday's speakers also were on the memorial's steps, but metal barriers kept people away from the Reflecting Pool and only a small group of attendees was allowed near the memorial itself.
There was a media area and VIP seating. Everyone else had been pushed back and watched and listened to the speeches on big-screen televisions. Police were stationed atop the Lincoln Memorial. After the speeches, marchers walked from there, past the King Memorial, then down the National Mall to the Washington Monument, a distance of just over a mile.
On the day of the anniversary, President Obama will speak from the steps of the Lincoln Memorial. He will be joined by former Presidents Bill Clinton and Jimmy Carter. Churches and groups have been asked to ring bells at 3 p.m. Wednesday, marking the exact time King spoke.
The Rev. Joseph Lowery, who founded the Southern Christian Leadership Conference with King, urged the crowd to continue working for King's ideals.
"We've come to Washington to commemorate," the 92-year-old civil rights leader said, "and we're going home to agitate."