Originally, the Schengen treaties and the rules adopted between them were officially independent of the EEC and its successor, the European Union (EU). In 1999, the Treaty of Amsterdam incorporated them into EU law, which codified Schengen into EU law and also introduced opt-outs for Ireland and the Kingdom, the latter having taken place since its withdrawal from the EU. EU Member States that do not yet have an opt-out and have not yet joined the Schengen area are legally obliged to do so if they meet the technical requirements. Although it is linked to EU legislation, several third countries are present in this region after signing the agreement. Schengen is a European zone made up of 26 countries that have abolished internal borders. Instead, these countries have focused globally on strengthening external borders. Citizens of the Schengen area can travel from one country to another within that territory, as if the whole region were one country. The Schengen countries have concluded agreements between them on visa policy, asylum policy and cooperation between their police and judicial authorities. In December 1996, two non-EU states, Norway and Iceland, signed an association agreement with the countries that signed the Schengen accession agreement.

Although this agreement never entered into force, the two countries were part of the Schengen area following similar agreements with the EU. [9] The Schengen Agreement itself was not signed by non-EU states. [10] In 2009, Switzerland officially concluded its accession to the Schengen area by adopting an association agreement by referendum in 2005. [11] The agreement began its concrete implementation five years later. On 19 June 1990, the same countries met to sign an agreement on the implementation of the Schengen Agreement, which was dealt with at the time: although Switzerland is not a member of the EU, it has strong economic and social relations with many Schengen states and, alongside Iceland, Norway and Liechtenstein (other third countries in the Schengen area) , it is part of the European Free Trade Association (EFTA). Switzerland became an integral part of the Schengen area after signing the agreement on 26 October 2004 and beginning to implement it on 12 December 2008. This article tells you more about the Schengen area in Europe, how it works, the participating countries, the protection of internal and external borders and much more. In addition, you will also find a short letter on the Schengen visa and how to travel in this area is ordered. With the entry into force on 1 May 1999 of the Schengen Protocol of the Treaty of Amsterdam of 2 October 1997, Schengen cooperation was transposed into EU law, initially solely on the basis of an international agreement.