If the first great scientific debate of the 1920s was over the size and composition of the Universe, the second was over the structure and nature of the atom. It turned out that the common-sense rules of our everyday world don't apply at the atomic level.
The French know the Roaring Twenties as the "crazy years," when Coco Chanel was the queen of fashion and Dada art was making everyone scratch their heads.
Music has always been a part of theatre, from opera to vaudeville. But in the 1920s, the first true stage musicals appeared.