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.  The Schengen Agreement itself was not signed by non-EU states.  In 2009, Switzerland officially concluded its accession to the Schengen area by adopting an association agreement by referendum in 2005.  Now that the Schengen Agreement is part of the Community acquis, it has lost to EU members the treaty status which could only be changed on its terms. Instead, changes are made in accordance with the EU`s legislative procedure under the EU treaties.  Ratification by the former signatory states is not necessary to amend or repeal all or part of the previous Schengen acquis.  Acts setting out the conditions for accession to the Schengen area are now adopted by a majority of the EU`s legislative bodies. The new EU Member States do not sign the Schengen Agreement as such, but are required to implement the Schengen rules within the framework of existing EU legislation, which any new entrant must accept. [Citation required] Before reaching an agreement with a neighbouring country, the Schengen State must obtain the authorisation of the European Commission, which must certify that the draft agreement complies with the regulation. The agreement can only be concluded if the neighbouring EEA state and the Swiss on the Schengen side of the border area at least grant reciprocal rights and accept the repatriation of those who have abused the border agreement.
Indeed, the Schengen Agreement paved the way for the release of the Schengen visa. Although this is not part of the original provisions of the agreement, the top 15 countries need only a visa for all. The Schengen visa may allow non-EU members to travel freely to the countries participating in the programme. Source: ec.europa.eu/home-affairs/what-we-do/policies/borders-and-visas/schengen_en With the Entry into force on 1 May 1999 of the Schengen Protocol to the Treaty of Amsterdam on 1 May 1999, Schengen cooperation was integrated into EU law, initially solely on the basis of an international agreement. Vatican City has an open border with Italy. In 2006, it expressed interest in joining the Schengen Agreements with a view to closer cooperation on the exchange of information and similar activities under the Schengen Information System.  Exceptionally, Italy allowed people to visit Vatican City without being accepted for an Italian visa, and then to be escorted by police between the airport and the Vatican or by helicopter. [Citation required] However, there is no customs union (including customs) between Italy and the Vatican, so all vehicles are controlled at the Vatican`s borders.