The stamp shows an artist's depiction of a 1950s-era photo of Parks, who was arrested in 1955 for refusing to give up her seat to a white man on a Montgomery, Alabama bus. At the time, blacks were treated as second-class citizens and regularly faced racism, discrimination and violence simply because of the color of their skin.
Parks' arrest sparked a 381-day boycott of the Montgomery bus system, nearly crippling the service because a majority of its riders were black. The protest had more wide-ranging effects, too. It helped bring prominence to Reverend Martin Luther King Junior, who went on to become one of the country's most outspoken advocates of racial equality and civil rights.
The boycott ended when the Supreme Court banned segregation on public transportation in 1956 and ordered Montgomery to integrate its buses. Of her historic decision to refuse to move to the back of the bus, where other black riders sat, Parks later said, "All I was doing was trying to get home from work."
The soft-spoken but feisty activist died in 2005 at the age of 92, becoming the first woman to lie in honor in the U.S. Capitol Rotunda.