During the 20s, there was an average of 70 banks failing each year nationally. After the crash during the first 10 months of 1930, 744 banks failed - 10 times as many. In all, 9,000 banks failed...
Banks loan your money out and then collect a profit from it. During the Great Depression people couldn't pay their loans back, which caused the bank's money supply to drop. Then when someone wanted...