Central banks are financial institutions that manage a country's currency, money supply, and interest rates. They play a crucial role in maintaining economic stability by implementing monetary policy, which influences inflation and employment levels. Examples of central banks include the Federal Reserve in the United States and the European Central Bank in the Eurozone. Central banks also oversee the banking system and act as a lender of last resort during financial crises. They regulate commercial banks to ensure they operate safely and soundly, protecting depositors and maintaining public confidence in the financial system.