Overview: By the end of the 19th century, factory owners realized that workers are just as much part of the company's capital as the machines are, and thought of ways to make these human machines work better, with nutrition and exercises. But the production line, invented in Chicago in 1871, did not catch on in the rest of the world until the World War I. Shortly after, the crises of the 1920s and 1930s saw the worker dramatically lose bargaining power.