Poland (Polish Polska [pɔlska] listen? / I, officially Rzeczpospolita Polska [ʐɛʈ͡ʂpɔspɔlita pɔlska]? / I, German Republic of Poland) is a parliamentary republic in central Europe. Capital and largest city in the country is Warsaw (Polish Warszawa), the largest metropolitan area, the metropolitan region Silesia. Poland is a structured into 16 provinces unitary state. With an area of ​​312,679 square kilometers Poland is the sixth largest country in the European Union and 38.5 million inhabitants, also the sixth most populous. There is primarily the oceanic climate in the north and west and the continental climate in the south and east of the country. In the early Middle Age tribes of the western Polans settled during the barbarian invasions in areas of present-day territory. A first written mention was in 966 place under the first historically attested Polish Duke Mieszko I, which the country opened to Christianity. 1025 the Kingdom of Poland was established, until it was united and in 1569 by the Union of Lublin to the Grand Duchy of Lithuania for the Royal Republic of Poland-Lithuania as one of the largest and most influential countries in Europe. During this time, the first modern constitution in Europe in 1791 was born. By the three partitions of Poland robbed late 18th century from the neighboring states of sovereignty, Poland regained its independence in 1918 with the Treaty of Versailles. The invasion of the German Reich and the Soviet Union at the beginning of World War II and the occupation regime killed millions, especially Jewish Poles, life. Since 1952, the Polish People's Republic standing under Soviet influence, there were 1989 political transformation to democracy, particularly through the Solidarity movement. Since 2004, Poland joined the European Union and a strong economic power in Central Europe. In terms of gross domestic product Poland is the zweiundzwanzigstreichste country in the world with the einundzwanzigsthöchsten purchasing power parity. In the Human Development Index Poland achieved the highest rating (very high). Located between West and East European cultural areas and marked by a checkered history, the country has developed a rich cultural heritage. Some of its citizens important contributions in science, mathematics, literature, film and music. Poland is a member of the United Nations, the OSCE, NATO, the Council of Europe and the European Union.