According to Wikipedia, Schengen area is the area including European countries that have abolished passport and any other type of border control at their mutual borders. This made it possible to visit all the neighboring countries in Schengen area and to cross border without further formalities. What this means is that with a schengen visa to any of these countries, you can visit the other countries without having to apply for visa again. Find below a list of countries that make up these schengen area;
Read also: Why You Should Study in a Schengen Country
List of the Schengen countries
Iceland (not a European Union Member State)
Liechtenstein (not a European Union Member
Norway (not a European Union Member State)
Swiss (not a European Union Member State)
Note: Is good to have in mind that European Union and the Schengen area are two different zones.
The world is about making things easier and faster, breaking protocols to the favour of everyone and that aloe gar birth to Schegen agreement.