The European Union (EU) is a group of 28 nations in Europe, formed in the aftermath of World War II. The first batch of countries joined in 1957, which included Germany, France, Italy, Belgium, Luxembourg and The Netherlands. In 1973, Denmark, Ireland and the UK joined. Greece joined in 1981, followed by Spain and Portugal in 1986 and Austria, Finland and Sweden in 1995. In 2004, 9 countries were added, 2 more in 2007, and finally Croatia in 2013 to bring the total to 28.
19 of the EU countries are also part of the Eurozone, which is a union of countries that have adopted the Euro as their official currency.
The Schengen Area includes 22 of the 28 EU countries, and entitles citizens of participating nations to travel freely between them. It also includes a few non-EU nations: Iceland, Norway, Switzerland and Liechtenstein. The area operates as a single nation with a uniform visa policy for purposes of international travel.