Official national administrative units:
Each national territory is divided into administrative units. The administrative units are divided by administrative boundaries. On the national level, data sets of administrative boundaries are available in most European countries. The national data sets differ with respect to resolution, data model and geometry of international boundaries.
This layers are specially useful for view  information and statistics, as a basis for generation of statistical map showing economic phenomena, demography etc.   

Coastal zone management areas.

Litoral areas used for management of environmental, social and economical resources.