They came in buses to Philadelphia, proudly wearing the t-shirts of their unions.

By mid-day Saturday, organizers of a national AFL-CIO rally claimed more than 35,000 attended, exceeding expectations. Police did not provide crowd estimates.

Democratic National Committee Chairwoman Debbie Wasserman Schultz, a Florida congresswoman took to the podium in the minutes following Mitt Romney's selection of Paul Ryan as his vice president.

When she mentioned Ryan, the crowd booed loudly. When they finished, she said, "I couldn't agree more. What a devastating impact a Romney-Ryan ticket would have on working families.

She added, "A child needs an education more than a million needs a tax break," she said to cheers from the crowd.

The crowd, which spilled over onto the steps of the Philadelphia Art Museum, also cheered when she invoked President Obama.

The event, Workers Stand for America, was organized by the AFL-CIO, to draw attention to issues involving the middle class.

"This is about changing the conversation in America," said Liz McElroy, secretary-treasurer of the Philadelphia AFL-CIO said Friday. "It's about making sure politicians of all stripes hear us."

The rally is open to all, union and nonunion workers alike. Organizers expected about 20,000 arriving on 300 buses from nearby states.

On Friday, union officials including Trumka signed the rally's centerpiece, America's Second Bill of Rights. Organizers will ask politicians to sign the five-point bill, which calls for the right to obtain full employment, participate in the voting process, form unions, receive a quality education, and be able to count on retirement and health-care benefits. The rally is drawing international media attention.