Henry Ford built a successful car company based on the principle of mass production of affordable cars. But his company was eclipsed by General Motors, which had a totally different marketing strategy: planned obsolescence.

Two of the twentieth century's worst technological innovations were leaded gasoline and chlorofluorocarbons. Both were introduced by the same person, engineer Thomas Midgley.

In the 1920s, most took it for granted that Western civilization and culture was the pinnacle of human accomplishment. A 23-year-old graduate student set out to prove that this was not the case, and that even the West had something to learn from other cultures.

Charles Darwin himself noted that the development of civilization had "stopped" evolution by natural selection within our own human species. This led others to speculate on whether society could purposefully direct human evolution.

The state of Tennessee had made it a criminal offense to teach evolution in the public schools. The trial of John Scopes became the most famous court case in America of the period.

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.

New York City grew to be the most populous city in the world in the 1920s, as well as home to the world's tallest buildings and the world's champion smart alecks.

In the early twentieth century, France had the world's largest motion picture industry, but it was soon eclipsed by that of the USA, a larger nation where movies were extremely popular. By 1920, 8 out of 10 motion pictures made in the world came from the United States.