Vienna is the national capital, largest city, and one of nine states of Austria. Vienna is Austria's most populous city, with about 1.9 million inhabitants, and its cultural, economic, and political centre. It is the 6th-largest city by population within city limits in the European Union.
Until the beginning of the 20th century, it was the largest German-speaking city in the world, and before the splitting of the Austro-Hungarian Empire in World War I, the city had 2 million inhabitants. Today, it is the second-largest German-speaking city after Berlin. Vienna is host to many major international organizations, including the United Nations, OPEC and the OSCE. The city is located in the eastern part of Austria and is close to the borders of the Czech Republic, Slovakia and Hungary. These regions work together in a European Centrope border region. Along with nearby Bratislava, Vienna forms a metropolitan region with 3 million inhabitants. In 2001, the city centre was designated a UNESCO World Heritage Site. In July 2017 it was moved to the list of World Heritage in Danger.