On February 7, 1992 the Maastricht Treaty was signed in Maastricht, Netherlands creating the European Union. The 12 original signatories were Belgium, Denmark, France, Germany, Greece, Ireland, Italy, Luxembourg, Netherlands, Portual, Spain, and the United Kingdom.
Finland and Sweden joined in 1995 and Austria in 1999.
In 2004, the EU saw its biggest enlargement when Cyprus, the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia and Slovenia joined.
Bulgaria and Romania joined in 2007, followed by Croatia in 2013.
Conspicuously absent is Norway, which has twice rejected membership in public referendums.
In March, 2017 the UK formally notified the European Council of tis intention to leave the EU by triggering Article 50 of the Lisbon Treaty. However the EU official website says “For the time being, the United Kingdom remains a full member of the EU and rights and obligations continue to fully apply in and to the UK.”