The internal structure of a state is determined by the state boundaries. To speak of state borders with regard to a uniting Europe is no easy task, since the import of the expression is changing within the framework of this integration. The outer borders of the EU lie along natural boundaries, and therefore may be clearly defined, while serving as protective enclosures for achievements which present inhabitants reached over many decades. In recent decades this produced a predominantly isolating tendency, and its liberalization in relation to penetrability may be mainly interpreted as a result of the expansion process. It seems appropriate to emphasise this notion, since after enlargement in 2004, today's Schengen border will partly become an internal one, and in parallel will be gradually pushed eastwards, creating a wall or barrier in regions where it was traditionally desirable to maintain penetrability.