WASHINGTON -- The crowd gathered early Wednesday morning for the celebration of Martin Luther King Jr.'s March on Washington and famous "I have a dream" speech 50 years ago.
President Barack Obama joked that his address marking the 50th anniversary of the historic "I Have A Dream" speech "won't be as good" as Dr. Martin Luther King's original.
King's 1,600-word address -- arguably one of the most important speeches of the 20th century -- became a crucial moment in the struggle for civil rights in the U.S.
Organizers of Wednesday's celebration expect up to 100,000 people.
Fifty years ago, King's passionate "I have a dream" speech was delivered from the steps of the Lincoln Memorial.
"... We will be able to speed up that day when all of God's children, black men and white men, Jews and Gentiles, Protestants and Catholics, will be able to join hands and sing in the words of the old Negro spiritual: Free at last! Free at last! Thank God Almighty, we are free at last!" King said.
President Obama will speak Wednesday afternoon during the celebration, along with King's daughter, former Presidents Bill Clinton and Jimmy Carter.
In an interview on the Tom Joyner Morning Show on CNN, President Obama said if King were alive today he'd be "amazed in many ways about the progress that we've made."
But Obama added that King would not be satisfied.
"When it comes to the economy, when it comes to inequality, when it comes to wealth, when it comes to the challenges that inner cities experience, he would say that we have not made as much progress as the civil and social progress that we've made, and that it's not enough just to have a black President," said Obama.
King was assassinated in Memphis almost five years after the March on Washington.