The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom or Britain, is a state in Europe, that consists of four states: England (London), Wales (Cardiff), Scotland (Edinburg), Northern Irelan (Belfast). Irish republic is an independent state. The capital is Dublin. The United Kingdom is the 22nd-most populous country, with an estimated 64.5 million inhabitants It is a constitutional monarchy with a parliamentary system of governance. Its capital city is London, an important global city and financial centre. This city is the fourth-largest in Europe and second-largest in the European Union.