The European Union (EU) is a group of 27 nations in Europe, formed in the aftermath of World War II. The first batch of countries joined in 1957, including Germany, France, Italy, Belgium, Luxembourg, and The Netherlands. In 1973, Denmark, Ireland, and the United Kingdom joined. Greece joined in 1981, followed by Spain and Portugal in 1986 and Austria, Finland and Sweden in 1995. In 2004, nine countries were added, two more in 2007, and finally Croatia in 2013 to bring the total to 28. On June 23, 2016, the United Kingdom voted to leave the EU.
Nineteen of the EU countries are also part of the Eurozone, a union of countries that have adopted the Euro as their official currency.
The Schengen Area includes 22 of the 27 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.