It’s impossible to overstate Martin Luther King, Jr.’s impact on modern American history. A Baptist minister who advocated the use of nonviolence to end racial segregation, King was the country’s most influential civil rights leader. He was instrumental in the passage of the Civil Rights Act, and the Voting Rights Act, and was awarded the Nobel Prize for Peace in 1964. This weekend marks the observance of his birthday as a national holiday, which is often celebrated with marches, parades and speeches by civil rights and political leaders.