US President Barack Obama (front R), First Lady Michelle Obama (front L), former US President Jimmy Carter (back L) and former US President Bill Clinton (back R) walk down the steps of the Lincoln Memorial to attend the 'Let Freedom Ring' commemoration event, in Washington, DC on August 28, 2013. The event was held to commemorate the 50th anniversary of the August 28, 1963 March on Washington led by the late Dr. Martin Luther King Jr., where he famously gave his 'I Have a Dream' speech. UPI/Michael Reynolds