Poland (Polish: Polska), officially the Republic of Poland (Polish: Rzeczpospolita Polska; Kashubian: Pòlskô Repùblika; Silesian: Polsko Republika), is a country in Central Europe, bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north. The total area of Poland is 312,679 square kilometres (120,726 sq mi), making it the 69th largest country in the world and the 9th largest in Europe. Poland has a population of over 38 million people, which makes it the 34th most populous country in the world and the sixth most populous member of the European Union, being its most populous post-communist member. Poland is a unitary state made up of 16 voivodeships. Poland is a member of the European Union, NATO, the United Nations, the World Trade Organization, the Organisation for Economic Co-operation and Development (OECD), European Economic Area, International Energy Agency, Council of Europe, Organization for Security and Co-operation in Europe, International Atomic Energy Agency, G6, Council of the Baltic Sea States, Visegrád Group, Weimar Triangle and Schengen Agreement.