Three decades ago, on November 1, 1993, the Maastricht Treaty came into force. Establishing a European Union (EU) between twelve member states (Belgium, Denmark, France, Germany, Greece, Ireland, Italy, Luxembourg, the Netherlands, Portugal, Spain and the United Kingdom), it introduced European citizenship, laid the foundations for a common internal market without customs duties, and paved the way for the introduction of a single currency: the euro. How did the Maastricht Treaty transform Europe? For whom have these transformations been - and still are - the most beneficial? Where do we stand today?