Wednesday marks the 75th anniversary of an arts event that rocked a nation grappling with racial segregation. On April 9, 1939 – Easter Sunday – black contralto Marian Anderson sang at the Lincoln Memorial after she was refused use of Constitution Hall.An internationally renowned opera singer, Anderson had performed in Europe, Russia, South America and across the United States, including a White House show for President Franklin Delano Roosevelt. But the Daughters of the American Revolution, which owned Constitution Hall, banned Anderson from performing in the auditorium. Eleanor Roosevelt, a member of the D.A.R., resigned to protest Anderson's exclusion. Listen here.