The enlargement of the European Union to include 10 new countries in May 2004 represents a political, economic and social event that is in many respects without equivalent. On 1 May 2004, the EU was enlarged to 25 member states by the addition of Cyprus, the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia and Slovenia. Of unprecedented proportions in terms of population, this integration mainly involves the central and eastern European countries (CEECs), whose level of development is distinctly lower than that of the EU 15. Hence, this enlargement raises numerous questions about the newcomers. They relate to the flexibility of their labour markets, the reform of their pension systems, the exchange rate policies, including the possible adoption of the euro, the financing of the EU, the proposals for the reform of the SGP and of the European system of central banks and finally the economic geography of the EU.