Great Depression,  began in 1929 and lasted until about 1939. It was the longest and most severe depression ever experienced by the industrialized Western world, sparking fundamental changes in economic institutions, macroeconomic policy, and economic theory.

the Great Depression caused drastic declines in output, severeunemployment, and acute deflation in almost every country of the world. Its social and cultural effects were no less staggering, especially in the United States, where the Great Depression represented the harshest adversity faced by Americans since the Civil War.