On 1 May 2004, ten new Member States joined the European Union, the largest enlargement in terms of population and number of countries in its history. The new Member States were Cyprus, the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia and Slovenia.

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Multimedia Centre
20th anniversary of the 2004 enlargement of the European Union - Multimedia Centre
<p>On May 1, 2004, ten&nbsp;new member states joined the European Union, marking the&nbsp;largest enlargement in terms of people and number of countries in the EU's history. Cyprus, Czech Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia, and Slovenia joined the Union, growing from 15 to 25 members.</p> <p>The European Parliament celebrates the 20th anniversary of these ten nations joining the European Union&nbsp;and engaging in the EP's democratic process to defend the interests of European citizens.</p>