listen)),[4] is a country in Central Europe. It is bordered to the north by the North Sea, Denmark, and the Baltic Sea; to the east by Poland and the Czech Republic; to the south by Austria and Switzerland; and to the west by France, Luxembourg, Belgium, and the Netherlands. The territory of Germany covers 357,021 square kilometers (137,847 sq mi) and is influenced by a temperate seasonal climate. With 82 million inhabitants, it accounts for the largest population among the member states of the European Union and is home to the third-largest number of international migrants worldwide.[5] A region named Germania inhabited by several Germanic peoples has been known and documented before AD 100. Beginning in the 10th century, German territories formed a central part of the Holy Roman Empire that lasted until 1806. During the 16th century, northern Germany became the centre of the Protestant Reformation. As a modern nation-state, the country was first unified amidst the Franco-Prussian War in 1871. In 1949, after World War II, Germany was divided into two separate states—East Germany and West Germany—along the lines of Allied occupation.[6] The two states were unified in 1990. West Germany was a founding member of the European Community (EC) in 1957, which became the European Union in 1993. It is part of the Schengen zone and adopted the European currency, the euro, in 1999.