The Great Depression was a global economic depression that lasted from 1929 until the 1940s. The Great Depression began with the American stock market crash on October 28 and 29, 1929. Unemployment rose and productivity fell throughout the Western world.
By 1929 companies had expanded to a point where they could no longer sustain themselves. Workers couldn't facilitate further growth, so a slowdown was inevitable. Corporate earnings greatly increased exponentially but wages rose more slowly, which caused a greater divide between the rich and poor - the richest one percent owned a third of America's wealth. This concentrated in the hands of a few limited the growth of the economy. The wealthy tended to save money that might have been put back into the economy, had it been spread among the middle and lower classes. Middle class Americans had already stretched their debt capacities by purchasing automobiles and household appliances on installment plans.
There were fundamental structural weaknesses in the American economic system. Banks operated without guarantees to their customers, creating a climate of panic when times got tough. Few regulations were placed on banks and they lent money to those who speculated recklessly in stocks. Agricultural prices had already been low during the 1920s, leaving farmers unable to spark any sort of recovery. When the Depression spread across the Atlantic, Europeans bought fewer American products, worsening the slide.