The European Union or EU is a supranational union of European states, the most recent acceding member being Croatia, which became full member on 1 July 2013. It has many functions, the most important being the establishment and maintenance of a common single market, consisting of a customs union, a single currency (adopted by 18 of the member states), a Common Agricultural Policy and a Common Fisheries Policy. The European Union also undertakes various initiatives to co-ordinate activities of the member states.