US Marking 50 Years Since 'Dream' Speech The United States has marked a turning point in its history with a rally held ahead of the 50th anniversary of Martin Luther King's March on Washington DC. Tens of thousands of people gathered on the National Mall to re-enact the moving civil rights rally where King delivered his "I Have a Dream" speech from the Lincoln Memorial. On Wednesday, the anniversary of the speech, church bells will ring out across the US while President Barack Obama will speak from the same steps. Martin Luther King III, the eldest son of the murdered civil rights leader, said at Saturday's event: "This is not the time for nostalgic commemoration. Nor is this the time for self-congratulatory celebration. The task is not done. The journey is not complete. We can and we must do more. Kathleen Johnson at the Martin Luther King March on Washington in 1963 Among those in the crowd to hear Dr King's speech 50 years ago were Kathleen Johnson and Jean McRae. Both women returned to the site on Saturday. Speaking about the address on August 28 1963, Ms Johnson told Sky News: "It was a beautiful day. It was white and black together. It was a united day. The image of her stumble into Washington DC's Reflecting Pool made magazines and newspapers across the country. Since then she has spent decades mobilising her community. She said: "Back then there was so much wrong that we needed to stand against. I had to be there I had to be apart of it and I still feel that way. Dr King delivered his speech on August 28, 1963 Greg Ward and his 12-year-old son, Benjamin, kept cool by fanning themselves with their "Voting Rights" banners, brought from their home state of Florida. The two stood among the thousands lining the Reflecting Pool under a brilliant blue sky, listening to a host of speakers with varying plights. Florida is the state in which George Zimmerman was found innocent in the killing of black teenager Trayvon Martin, whose name and face adorns countless banners and T-shirts at Saturday's event. Sky's US correspondent Amanda Walker said they want a repeal of the stand your ground law that they say allowed Zimmerman to walk free. She added: "It's the most tangible sign of the census of the crowd: Martin Luther King's dream, shared on the steps of the Lincoln Memorial, has yet to be fulfilled." Mr Ward echoes the words of America's first black president - 'Trayvon could have been my son'. He said: "It was important for us to be here. What happened in Florida broke my heart - it took us back. It could have been Benjamin. We need to move forward and this march can help that. Patricia Major sat in the fold up chair she brought on the train from Connecticut. She carried a Trayvon Martin banner and said: "That verdict was important but it's not the only issue. Immigration reform, voting rights, poverty - we are not there yet. Sure we have a black president but that doesn't make US society postracial. Many other events are planned around the country over the coming days, giving Americans a chance to reflect on race relations. An estimated 250,000 people of all races descended on the Mall on August 28, 1963, chanting "Equality now!" and singing "We Shall Overcome," in what was officially billed as the March on Washington for Jobs and Freedom. Millions more watched on television, among them President John F. Kennedy, who until then had been dragging his feet on legislation to end racial segregation in conservative Southern states.