The Prayer Pilgrimage for Freedom was held in Washington, D.C. on May 17, 1957. The event was attended by 27,000 people! Click this link to watch a film clip from that day on the Civil Rights Digital Library website: http://crdl.usg.edu/cgi/crdl?action=retrieve;rset=001;recno=1;format=_video
Photo by Lee Friedlander courtesy Fraenkel Gallery, San Francisco.
