LIVE: Obama speaks on the 50th anniversary of the March on Washington

Today marks the 50th anniversary of Martin Luther King Jr.’s speech to thousands assembled in front of the Lincoln Memorial in Washington, D.C., when he famously told the world about his dream that his children would "be judged on the basis of the content of their character, not the color of their skin." President Barack Obama, standing in the same spot and following speeches by former presidents Jimmy Carter and Bill Clinton, addresses a massive crowd surrounding the famous reflecting pool. The speech starts at 3 p.m.