The European Union is a group of 28 countries working together to improve their economies and politics. They started by forming the European Coal and Steel Community in 1951 to prevent future wars between France and Germany. In 1992, they signed the Maastricht Treaty to increase cooperation and create a common European currency. This led to the establishment of the European Monetary Union in 1992 and the introduction of the euro in 1999. The goal is to make it easier for countries in the EU to trade with each other by using the same currency.