After World War I, the economy boomed, leading historians to refer to the 1920s as the "Second Industrial Revolution." The economy of the 1920s was a key change as it brought about new mass production and consumption and set the stage for the ever-looming Great Depression. The 1920s saw a great boom in mass production, which reduced the prices of technological products. This decade saw a huge expansion of consumer credit, where Americans were used to finance the purchase of new products such as the growing popularity of cars and radios, created by mass production. The automobile, film, radio, and chemical industries boomed during this decade – one of the largest being the automobile industry. While Henry Ford was producing mass-produced automobiles, approximately 1.9 million cars had been sold by the end of 1929. The economics of the automobile company had a great impact not only on business, but also on society . Henry Ford, who had revolutionized the new workers' day and the concept of mass production, had indirectly influenced the way Americans lived and behaved. Cars fueled the growth of other markets, such as steel, rubber, glass, and oil. It also fostered urban and suburban growth, where a new class of Americans was emerging. Now citizens could go to new places, meet new people, act differently... etc... The speed with which mass-produced products spread across America was astonishing: not only automobiles but also machines washing machines, refrigerators, electric irons, electric and gas stoves. --a multitude of inventions and technologies that have significantly transformed that part of economic life that takes place within the household. However, this development and the rise of the American economy have led to a major consequence. Indeed, one of the major consequences of mass production was the creation of a stock of capital goods intended for domestic production. And that of course was the biggest key change… because it seemed like the stock market and industrial rise of the 1920s would last forever. This rise in the stock market led to the Great Depression…a downward spiral of economic depression. The booming economy of the 1920s led to the Great Depression. This affected almost the entire industrialized world. The main cause of the depression was the unequal distribution of wealth throughout the 1920s and the extensive stock speculation that took place during the latter part of the same decade. The maldistribution of wealth in the 1920s existed on several levels.