The Euro currency was introduced and adopted by 11 Member States.
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The United Kingdom left the European Union, also known as 'Brexit.'
The European Union formally opened accession negotiations with Ukraine.
The European Union's climate service declared that 2023 was the hottest year on record.
The name 'Euro' was officially adopted for European Currency.
Romania and Bulgaria signed the European Union's Treaty of Accession, the last step to joining the Union.
