Can a bank hold millions of dollars?

I'm curious, is it feasible for a bank to possess millions of dollars in its vaults? How does a bank ensure the safety and security of such a vast amount of funds? Do they utilize special storage facilities or advanced security measures to protect these assets? Additionally, how does a bank manage the liquidity of such funds, ensuring they are available for customers and investments while still maintaining a healthy balance sheet? I'm eager to understand the intricacies and mechanisms behind how a bank can safely hold and manage such a significant amount of capital.