Opera singer Marian Anderson sings My Country Tis of Thee on the steps of Lincoln Memorial in 1939,

The video captures a significant civil rights gathering at the Lincoln Memorial, where 75,000 people attended an outdoor concert. A grand piano was brought up the steps for the first time, and the crowd listened to a moving tribute in song to Mrs. Roosevelt and her passionate beliefs. Marian Anderson performed 'My Country, 'Tis of Thee', delivering a powerful message of freedom and patriotism.

Describe the atmosphere of the crowd that gathered that day.

What message does the phrase 'Let freedom ring' convey?