Germany is a federal parliamentary republic in central-western Europe. It includes 16 constituent states, covers an area of 357,021 square kilometres (137,847 sq mi), and has a largely temperate seasonal climate. With about 82 million inhabitants, Germany is the most populous member state of the European Union. After the United States, it is the second most popular immigration destination in the world. Germany's capital and largest metropolis is Berlin, while its largest conurbation is the Ruhr (main centres: Dortmund and Essen). The country's other major cities are Hamburg, Munich, Cologne, Frankfurt, Stuttgart, Düsseldorf, Leipzig, Bremen, Dresden, Hannover and Nuremberg.
Various Germanic tribes have inhabited the northern parts of modern Germany since classical antiquity. A region named Germania was documented before 100 AD. During the Migration Period the Germanic tribes expanded southward. Beginning in the 10th century, German territories formed a central part of the Holy Roman Empire. During the 16th century, northern German regions became the centre of the Protestant Reformation. The remains of the Holy Roman Empire formed the German Confederation in 1815, while the German revolutions of 1848–49 established major democratic rights first.