Final answer:
A bank run is when depositors rush to their banks to withdraw their money due to concerns about the bank's financial stability.
Step-by-step explanation:
A bank run would occur when depositors rush to their banks, trying to be one of the lucky few to withdraw their money while the bank still has reserves left. A bank run typically happens when there are rumors or concerns about the financial stability of a bank. Depositors fear that they may lose their money if they don't withdraw it immediately. This phenomenon has often been observed during times of economic crisis, such as the Great Depression.