Original 1960's Placard / Protest Sign Used In Washington DC Civil Rights March

A little beat and worn, but unquestionably an original 1960's Placard / Protest Sign used in a Washington DC Civil Rights March. The exact march has been lost to time. "I have a dream... One America". after the iconic Martin Luther King Jr speech - was delivered in 1963. This I assume would date after that and need to do my research to find what dates subsequent civil rights marches were held. One color ink on card stock measuring approx. 22” x 14”. The most significant thing for me is you can see the staple holes where this was attached to a wooden pole for the protest march.