Ku Klux Klan marching down Pennsylvania Ave., Washington, D.C ca. 1926

Ku Klux Klan marching down Pennsylvania Ave., Washington, D.C ca. 1926. (Photo by: Hum Images/Universal Images Group via Getty Images)

Hate on the March. In September 1926, with the terror group ascendant, a KKK parade drew 30,000 Klansmen to Washington, DC, in a display of strength. (Hum Images/Getty Images)