The euro is the official currency used by many countries in the European Union. It was introduced in 1999 and became physical cash in 2002. The euro is represented by the symbol "€" and is divided into 100 cents. It helps facilitate trade and travel among member countries by providing a common currency. Using the euro makes it easier for people to shop and travel across Europe without needing to exchange money. Countries like Germany, France, and Italy all use the euro, making it one of the most widely used currencies in the world.