World War I is known as the first "modern" war, because a new kind of warfare was utilized, new technologies were operated, planes fought in combat, and women played a key role in manufacturing and other positions formerly held by men. In the shift from wartime to peacetime, many women were reluctant and rebellious to return to their positions of domesticity, and sought other opportunities. With the passing of the nineteenth amendment in 1920, younger women felt even more liberated, and changed their style of dress, hair and life: skirts became shorter, hair was bobbed, and many women began to smoke. Along with this questioning of traditional values, one can see a steady increase in the divorce rate and a sharp drop in the number of marriages. Religion, in a traditional way of life, was also challenged with new theories such as that of evolution and natural selection, literal interpretation of Scripture, and the incorporation of contemporary trends, such as jazz, into one's image of heaven.
During this time, American cities grew larger at an alarming rate; the sources of this growing population were immigrants. These newcomers were a significant part of the disharmony that existed between the old and the new in the 1920s, because they presented diversity to a people who were striving become more provincial and who wanted to preserve "Americanism." It was these groups that the Ku Klux Klan fought to