9 April 1939. World-renowned contralto Marian Anderson sang to more than 75,000 at the Lincoln Memorial. Her performance came after months of controversy over the concert venue which became a national discussion on discrimination.

Previously, the Daughters of the American Revolution (DAR) rejected her request to sing at Constitution Hall in Washington DC. First Lady Eleanor Roosevelt, a member of the DAR at the time, resigned her membership and helped to organize the concert.

https://www.npr.org/2019/04/09/711536559/80-years-ago-marian-anderson-performed-for-some-75-000-people-at-the-lincoln-mem