EU By Leonardo Pagliai 1957 European Community Treaty of Rome 1973 Denmark,Ireland,United Kingdom joined the Eu 1981 Greece joined the EU 1986 Spain and Portugal joined the EU 1989 Fall of Berlin Wall 1995 Sweden,Finland and Austria joined the EU 2004 Members Countries Become 25 2007 Lisbon treaty 2013 Croatia joined the EU 2020 Brexit