What is run on the bank? who does this fill with dread?

One morning on her way to work, Marija sees a large crowd gathered outside her bank. Panicking, she asks numerous people about the situation. They tell her there is a “run on the bank,” and everyone is attempting to withdraw their money at once because they are afraid that the bank is going to fail. Marija begins to claw and fight her way through the crowd, but realizes she does not have her bankbook and so she has to go back home to collect it. When she returns, the line to get into the bank extends for several blocks. Marija worries that there will be no more money left when she is finally able to get inside.