Singers Joan Baez and Bob Dylan perform together during the March on Washington for Jobs and Freedom in this August 28, 1963 file photo shot by US Information Agency photographer Rowland Scherman and provided to Reuters by the US National Archives in Washington on August 21, 2013. In the coming week, Washington will play host to an array of events marking the 50th anniversary of the march and the Rev. Martin Luther King Jr.'s I Have A Dream speech. [Photo/Agencies]