See an iReporter's view of preparations for Saturday's rally.

Washington (CNN) -- A coalition of liberal and progressive groups, including unions and civil rights activists, rallied in Washington Saturday to press for good jobs, immigration and education reform and to make a show of strength one month out from midterm elections.

The "One Nation Working Together" rally was held at the Lincoln Memorial, just five weeks after Tea Party enthusiasts met in Washington.

NAACP President Ben Jealous told CNN the "One Nation" movement is not "the alternative to the Tea Party, we're the antidote to the Tea Party."

Jealous said he welcomes Tea Party members, but takes issue with extremists in the movement who critics say harbor racist views. Still, Jealous says he invited a well-known conservative to speak at Saturday's rally. He refused to name the person, who did not address the group. It was not immediately clear why.

Jealous said the coalition of liberal organizations came together to offer a positive alternative to negative rhetoric, and to demand better education and more economic opportunities. The "One Nation" movement, he said, would rather see jobs for 99 percent of Americans instead of tax cuts for one percent of Americans.

"We want America to be something that represents every kind of diversity in this country," said Sergio Sanchez, with the Farm Labor Organizing Committee, who attended the rally. "We're here because we want to show that we have a presence and that we want America to head in the right direction."

The rally began with an Interfaith service at 11 a.m. ET. As the service started, crowds were already beginning to thicken at the National Mall near the Lincoln Memorial, where the rally took place.

Rally signs range from benign to fiery. They include: "The Left is What's Right," "Stop Racism Now," We March for Hope Not Hate," "Proud to be a Democrat," "Stand with Obama," "Silence GOP Lies,""No Cuts to Social Security" and "Axis of Ignorance - Tea Party, Republicans, Fox News."

Organizers claim a wide range of supporters, some of whom are already associated with liberal causes -- like union workers, environmentalists, gay activists and student leaders. But "One Nation" also claims backing from less obvious quarters -- like senior citizens, veterans and faith leaders.

The group's website sets out a list of basic principles and priorities. These include direct assistance for unemployed workers and assistance for small businesses and local governments trying to hire new workers; a minimum wage increase; health care reform; immigration policy changes; increased bankruptcy and foreclosure protection; and more money for education, from kindergarten through college.

The rally comes on the heels of another rally by conservatives in August.

Commentator Glenn Beck drew Tea Party activists to the Lincoln Memorial for his revival-style rally August 28. The timing and site of the rally provoked controversy among civil rights activists because it was on the 47th anniversary of the Rev. Martin Luther King Jr.'s "I Have a Dream" speech and in the same place.

Around noon Saturday, a variety of speakers and performers began to take the stage. The program mixed speeches by activists and orators with music, historical readings, and even video clips.

Among those who spoke was the Rev. Al Sharpton, who used the opportunity to urge people to get involved and vote in the next election.

"We've got to get ready for the midterm exam. We can't stop in '08!" he said to roaring applause.