On May 1, 2004, under the Accession Treaty, signed a year earlier in Athens, Poland joined the European Union.
16 years ago, the borders of the EU changed significantly – together with us, full members of the Union, there were nine countries: Cyprus, the Czech Republic, Estonia, Lithuania, Latvia, Malta, Slovakia, Slovenia and Hungary. It was the largest extension in the history of the community. Since then, three more countries have joined the EU: Romania, Bulgaria and Croatia. In 2016, the United Kingdom, as the first of EU countries, decided to leave the EU.