Flag of Germany with coat of arms (unofficial)

Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen constituent states have a total population of over 82 million in an area of 357,596 km2 (138,069 sq mi), making it the most populous member state of the European Union. It borders Denmark to the north, Poland and the Czech Republic to the east, Austria and Switzerland to the south, and France, Luxembourg, Belgium, and the Netherlands to the west. The nation's capital and most populous city is Berlin and its main financial centre is Frankfurt; the largest urban area is the Ruhr. Settlement in the territory of modern Germany began in the Lower Paleolithic, with various tribes inhabiting it from the Neolithic onward, chiefly the Celts. Various Germanic tribes have inhabited the northern parts of modern Germany since classical antiquity. A region named Germania was documented before AD 100. In 962, the Kingdom of Germany formed the bulk of the Holy Roman Empire. During the 16th century, northern German regions became the centre of the Protestant Reformation. Following the Napoleonic Wars and the dissolution of the Holy Roman Empire in 1806, the German Confederation was formed in 1815. Formal unification of Germany into the modern nation-state commenced on 18 August 1866 with the North German Confederation Treaty establishing the Prussia-led North German Confederation, which became the German Empire in 1871. After World War I and the German Revolution of 1918–1919, the Empire was replaced by the Weimar Republic. In 1949, after the war and a period of Allied occupation, Germany was organised into two separate polities with limited sovereignty: the Federal Republic of Germany, or West Germany, and the German Democratic Republic, or East Germany. Berlin continued its de jure Four Power status. The Federal Republic of Germany was a founding member of the European Economic Community and the European Union in 1951, while the German Democratic Republic was a communist Eastern Bloc state and member of the Warsaw Pact. After the fall of the communist led-government in East Germany, German reunification saw the former East German states join the Federal Republic of Germany on 3 October 1990. Germany is a developed country with a strong economy; it has the largest economy in Europe by nominal GDP. As a major force in several industrial, scientific and technological sectors, it is both the world's third-largest exporter and importer. It offers social security, a universal health care system, and tuition-free university education. Germany is part of multiple international organisations and forums. It has the third-highest number of UNESCO World Heritage Sites: 54, of which 51 are cultural.