MADISON, Wis. -

Thousands filled the National Mall to mark the 50th anniversary of the March on Washington for Jobs and Freedom.

Members of the King family and three U.S. presidents helped ring a bell marking the hour Dr. Martin Luther King Jr. delivered his landmark speech.

Fifty years to the day after King’s historic “I Have a Dream” speech, the nation’s first black president stood in the same place the civil rights icon stood at the Lincoln Memorial.

“Because they marched, city councils changed and Congress changed and yes, eventually, the White House changed,” President Barack Obama said.

“It’s an opportunity today to recall where we once were in this nation and to think about that young man who, at 34 years old, stood up here and was able to force an entire country to wake up, to look at itself and to eventually change,” said Oprah Winfrey.

Five decades later, more than half of Americans believe race relations are generally good but a CBS news poll released Wednesday shows room for improvement.

Sixty two percent of blacks say they have experienced racial discrimination compared with 29 percent for whites.

Back in Madison, people also remembered the momentous speech.

A small group came together in Madison to honor MLK by meeting at the Martin Luther King Jr. statue to share their thoughts on King and the progress made in this country long after his death.