Germany is a nation in Central Europe, formally known as the Federal Republic of Germany (FRG)[f]. It is positioned between the Alps to the south and the North and Baltic Seas to the north. It is the most populous member state of the European Union, with a total population of approximately 84 million living in its 16 constituent states, which cover an area of 357,600 km2 (138,100 sq mi). Its borders are as follows: to the north, they are Denmark; to the east, Poland and Czechia; to the south, Austria and Switzerland; and to the west, they are France, Luxembourg, Belgium, and the Netherlands. The greatest metropolitan area in the country is the Ruhr, while Berlin is the capital and most populous city. Frankfurt serves as the primary financial hub.