Schengen is a territory in Europe that comprises of 26 countries that signed a treaty to end internal border checkpoints and controls. With a Schengen visa, you can travel freely throughout the Schengen zone.
A citizen of a member state passing from one Schengen country to another Schengen country does not need to undergo border checks, which means he or she does not have to show a travelling document at the borders. Below is a list Of All Schengen Countries as of 2020.
List Of All Schengen Countries 2020