This print by Anton Refregier, a copy of a mural he painted in a San Francisco post office, glorifies labor's side in the hard-fought struggles of the 1930s.

Lewis Hine's photo shows the young children who worked long hours in early-20th-century factories.

An engraving from Harper's Weekly of the bombing that tarnished labor's image in the turbulent 1880s.

This girl, only 4'3" tall, had worked in the mill for a year, sometimes at night, for 48¢ a day.

Workers pass the time during the 44-day strike at the Flint, Michigan, GM plant that brought in the United Auto Workers.

The man who was most influential in shaping the labor movement in the United States.

The longtime AFL-CIO leader, an icon of Big Labor.

César Chávez, co-founder of the United Farm Workers Union, at a 1972 rally.