In 1985, the countries that had signed the Schengen Agreement started eliminating internal border controls. Currently, the Schengen Area consists of 26 European countries: 22 EU member states and 4 countries from outside the EU.
Anybody, regardless of whether he or she is a citizen of an EU member state or not, has the right to move freely within the Schengen Area, without a need for any additional visas or permits. All you need is an ID.
The right to travel freely within the Schengen Area provides many benefits not only for those who wish to do business in Europe (because now if you need to meet a business partner you can avoid the red tape related to getting a visa), but also for holiday-makers and other people travelling outside their country.
The following countries have joined the Schengen Area, which eliminates internal border controls:
It is important to note that a person who is not a citizen of a Schengen country is allowed to stay in another Schengen country without a visa for up to 3 months.