The Nobel Peace Prize honors different kinds of work for world peace.

The people you see here have all won the Nobel Peace Prize in previous years. Winners of this prize are known as Nobel laureates. Mother Teresa was a Roman Catholic nun who won the peace prize for her efforts to help poor people in India. She worked for more than 45 years helping the poor, the sick, and the dying in Kolkata, India. She founded the Missionaries of Charity group, which today has thousands of nuns in locations all over the world. Do you think Mother Teresa was a good choice to win the Nobel Peace Prize?

The Rev. Martin Luther King Jr. was awarded the Nobel Peace Prize in 1964. Martin Luther King was a leader of the civil rights movement in the United States in the 1960s. He fought to end segregation in the American South. Segregation is the forced separation of different races -- in this case, black people and white people. The Rev. King promoted civil disobedience to end segregation. Civil disobedience means peacefully refusing to follow certain laws as a form of protest. Martin Luther King led a boycott of city buses in Montgomery, Alabama. He and many other black people refused to ride the city's buses to protest the rules that black people had to sit in the back of the bus.

Former U.S. Vice President Al Gore won the Nobel Peace Prize last year. He was awarded the prize for his efforts to educate people about global warming and prevent environmental damage caused by it. Was he a good choice to win the prize?