It is an agreement on raising passport and visa control between a number of EU countries. It was signed in Shengen city of Luxemburg, which is on the borderline of Luxemburg, Germany and France. Shortly after signing the agreement several other countries joined the agreement as well, and in the end of 2007 the agreement was signed by 30 countries. Its status on border control elimination covers 24 countries such as Austria, Belgium, Germany, Denmark, Estonia, Iceland, Spain, Italy, Latvia, Poland, Lithuania, Luxemburg, Greece, Hungary, Malta, the Netherlands, Norway, Sweden, Check, Portugal, Slovakia, Slovenia, Finland and France. All these countries together are the Shengen zone. A number of other countries, where the Shegnen agreement has been enforced already, have not eliminated the border control, thus they are still out of the Shengen zone.
Besides Norway and Iceland, all the other Shengen countries are members of the European Union.
Five members of the European Union have already signed the Shengen agreement but still are out of the Shengen zone because they have not either raised the border control yet (the Great Britain, Ireland), or are going to do that in the future (Bulgaria, Cyprus, Switzerland, Romania).
As a result of the referendum on June 5, 2005, the citizens of Switzerland voted for joining the Shengen zone.
On March 15, 2006, the Shengen codex was adopted, which brought some changes in the Shengen Convention as well.
On December 21, 2007, the land and sea border control was eliminated in 9 countries of the Shengen zone (Estonia, Latvia, Poland, Lithuania, Hungary, Malta, Check, Slovakia and Slovenia), and the air border control was eliminated on March 30, 2008.