Martin Luther King was an activist and spokesman in the Civil Rights Movement during the 1950s and 1960s. He protested against racial discrimination in the USA. It was very difficult for black people in the USA at that time, as there were lots of racial and social problems.
Segregation of black and white people was the law in the South and other parts of America and Martin Luther King became very famous for his peaceful protests against this situation. His birthday is on the 15th of January, but Martin Luther King's day isn't always on this day. The holiday is always on the third Monday of January. This year is the 18th of January.
Martin Luther King's most famous speech is called "I have a dream". He gave this speech on the 28th of August 1963 in front of more than 250.000 civil rights supporters. It is one of the most famous and recognised speeches ever.
Nowadays, to celebrate Martin Luther King's day people try to help others by donating their free time. Some people help`the poor or go to special services dedicated to remembering this very brave and important man.