The European Union began as the European Coal and Steel Community in 1951 and evolved through various stages, including the establishment of the European Economic Community in 1958 and the Maastricht Treaty in 1993. It currently includes 27 member countries and functions as the world's largest economy, with a GDP of $15.821 trillion and a population of 501 million. Key entities within the EU include the Eurozone, which consists of 17 members using the euro, and the European Central Bank, tasked with monetary policy.