The Ku Klux Klan was formed to intimidate former slaves and prevent them from exercising their right to vote following the Civil War. In 1915, white men and women formed a second Klan because they feared that the growing numbers of African Americans, recent immigrants, Jews, and Catholics threatened their interests. Membership in the second Klan peaked in the early 1920s with an estimated three million members. By 1925, however, the Klan was in decline. Hoping to show their continued relevance, forty thousand members of the Klan marched down Pennsylvania Avenue on August 8, 1925.