The Great Depression was 100% caused by the Federal Reserve.
The Federal Reserve slashed interest rates in the mid 1920s, causing a vast expansion in the money supply. This encouraged everyone to load up on debt and mortgage their property to the hilt. The insiders who control the Federal Reserve knew that interest rates were going to be jacked up in 1929. They stopped issuing loans and sold their stock shares a few months before the crash. The bankers cleaned up by issuing loans and stock during the economic boom, and then buying assets cheap after the crash. The bankers issued loans to themselves to buy up property cheap at the bottom of the Depression. When Roosevelt confiscated the gold in 1933, defaulted on the dollar, and devalued the dollar, all those loans could be repaid in devalued dollars. The international banking cartel cleaned up on each leg of the boom, bust, and default on the dollar.
The Great Depression caused banks to confiscate a lot of property that previously belonged to farmers and small business owners. The US was turned from a nation of farmers and small business owners into a nation of wage slaves and welfare recipients. The welfare state was created to compensate for the damage caused by the Federal Reserve.
The idea that the Great Depression was caused by greedy speculators and economic excess is a lie. The Federal Reserve's loose monetary policy in the 1920 encouraged speculation and the use of leverage. The speculators were merely following the rules of a corrupt monetary system. The insiders knew when the rules would change form easy money to tight money, and they cleaned up.