The Roaring Twenties characterizes the distinctive cultural edge of the 1920s, principally in American cities, but also in Berlin and Paris, for a period of sustained economic prosperity. The phrase emphasizes the period's social, artistic, and cultural dynamism. "Normalcy" returned to politics in the wake of World War I, jazz music blossomed, the flapper redefined modern womanhood, Art Deco peaked, and finally the Wall Street Crash of 1929 ended the era, as the Great Depression set in worldwide. Economically the era saw the large-scale diffusion and use of automobiles, telephones, motion pictures, and electricity, unprecedented industrial growth, accelerated consumer demand and aspirations, and significant changes in lifestyle and culture. The media focused on celebrities, especially sports heroes and movie stars, as cities rooted for their home team and filled the new palatial movie theaters and gigantic stadiums. In most major countries women were voting for the first time.

The social and cultural features known as the Roaring Twenties began in leading metropolitan centers, especially Chicago, New Orleans, New York City, Philadelphia, Paris and London, then spread widely in the aftermath of World War I. Thus when Germany could no longer finance war reparations to the Allies (and they could not repay their loans to the U.S.), Washington came up with the Dawes Plan and Wall Street invested heavily in Germany, which repaid its reparations to nations that in turn used the dollars to pay off their war debts to Washington. By the middle of the decade, prosperity was widespread, with the second half of the decade later becoming known as the "Golden Twenties". In France and francophone Canada, they were also called the "années folles" ("Crazy Years").