Vienna is the capital of the Republic of Austria and one of the nine states of Austria. Vienna is Austria's primary city, with a population of about 1.7 million and is by far the largest city in Austria, as well as its cultural, economic, and political centre. It is the 10th largest city by population in the European Union. Vienna is host to many major international organizations such as the United Nations and OPEC. 

In 2001, the city centre was designated a UNESCO World Heritage Site.