Final answer:
The conflict between modern thinkers and fundamentalists in the 1920s culminated in the Scopes Trial of 1925, which centered on the teaching of evolution in schools and symbolized the era's cultural divisions.
Step-by-step explanation:
The conflict between modern ideas and fundamentalist beliefs dramatically escalated in 1925 with the event known as the Scopes Trial, also referred to as the Scopes Monkey Trial. This legal battle centered around John Scopes, a biology teacher in Dayton, Tennessee, who was charged with violating state law by teaching Charles Darwin's theory of evolution. The trial highlighted the cultural divide between the newly emerging urban modernism, which often embraced scientific ideas and more permissive social mores, and rural traditionalism, which held onto established religious and cultural norms. The Scopes Trial became a nationwide media spectacle, with prominent figures like William Jennings Bryan defending traditional beliefs and Clarence Darrow advocating for academic freedom. Ultimately, the trial reflected the deep tensions of the era surrounding education, religion, and the right to intellectual exploration.