Treaties of the European Union the Functioning of the European Union (originally signed in Rome in 1957 as the Treaty establishing the European Economic Community, aka The Treaty of Rome), lay out how the EU operates, and there are a number of satellite treaties which are interconnected with them. The treaties have been repeatedly amended by other treaties over the 65 years since they were first signed. The consolidated version of the two core treaties is regularly published by the European Commission. The two principal treaties on which the EU is based are the Treaty on European Union (TEU; Maastricht Treaty, effective since 1993) and
Statistical Classification of Economic Activities in the European Community systems: NACE uses four hierarchical levels: The first four digits of the code, which is the first four levels of the classification system, are the same in all European countries. National implementations may introduce additional levels. The fifth digit might vary from country to country and further digits are sometimes placed by suppliers of databases. The 21 Level 1 codes are: For a full list of NACE Codes, please refer to: Statistical Classification of Economic Activities in the European Community The Statistical Classification of Economic Activities in the European Community, commonly referred to as NACE (for the French term ""nomenclature