If you click here you will to a CBS article on the restoration of 33 dioramas created for the American Negro Exposition of 1940. It was created to celebrate African American achievements since the end of slavery.
There had never been anything like it. President Roosevelt pushed the button that turned the lights on Opening Day. There were all kinds of exhibits, including a Hall of Fame honoring notable African Americans. Jazz legend Duke Ellington entertained the crowd. And at the center of it all was a huge hall featuring 33 dioramas. It was trying to celebrate the enormous contribution of Black Americans to the USA, and change attitudes. It was perhaps an early manifestation of Black Lives Matter.