Germany (officially the Federal Republic of Germany), is a country in Western and Central Europe. Germany is a federal parliamentary republic of sixteen states. The capital and largest city is Berlin. It covers an area of 357,021 km2 and has a largely temperate seasonal climate. With 81.8 million inhabitants, it is the most populous member state and the strongest economy of the European Union. It is one of the major political powers of the European continent and a technological leader in many fields. A region named Germania, inhabited by several Germanic peoples, was documented before AD 100. Beginning in the 10th century, German territories formed a central part of the Holy Roman Empire of the German Nation, which lasted until 1806. During the 16th century, northern German regions became the centre of the Protestant Reformation while southern and western parts remained dominated by Roman Catholic denominations. The different German states became first unified in 1871, with the inception of the German Empire. The Weimar Republic was proclaimed in 1918, followed by the Third Reich in 1933. The latter period was marked by a dictatorship and the initiation of World War II in 1939. After 1945, Germany was divided by allied occupation, and evolved into two states, East Germany and West Germany. In 1990 Germany was reunified.