Germany or Deutschland, formally the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated between the Baltic and North seas to the north, and the Alps to the south. Germany 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 largest city is Berlin and its financial centre is Frankfurt. Various Germanic tribes have inhabited the northern parts of modern Germany since classical antiquity. A region named Germania was documented before AD 100. After the end of World War II in Europe and a period of Allied occupation, Germany was divided into the Federal Republic of Germany, generally known as West Germany, and the German Democratic Republic, East Germany. The Federal Republic of Germany was a founding member of the European Economic Community and the European Union, while the German Democratic Republic was a communist Eastern Bloc state and member of the Warsaw Pact. After the fall of communism, German reunification saw the former East German states join the Federal Republic of Germany on 3 October 1990—becoming a federal parliamentary republic. Germany is a great power with a strong economy; it has the largest economy in Europe, the world's fourth-largest economy by nominal GDP. As a global leader in several industrial, scientific and technological sectors, it is both the world's third-largest exporter and importer of goods. It has the third-greatest number of UNESCO World Heritage Sites.