What is schengen?

Some articles on schengen:

Schengen Area - Regulation of External Borders - Entry Conditions For Third-country Nationals
... A Schengen visa or a visa exemption does not, in and of itself, entitle a traveller to enter the Schengen Area ... The Schengen Borders Code lists requirements which third-country nationals must meet to be allowed into the Schengen Area ... is certain to be admitted, or is in a position to acquire such means lawfully The Schengen Information System does not contain an alert for refusal of entry concerning the traveller, and The traveller is not ...