Vienna is the capital and the largest city of Austria, and one of the nine states of Austria. Vienna is Austria's primary city, with a population of about 1.731 million (2.4 million within the metropolitan area, more than 25% of Austria's population), and is by far the largest city in Austria, as well as its cultural, economic, and political centre. It is the 9th-largest city by population 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. Vienna is host to many major international organizations, including the United Nations and OPEC. The city lies in the east 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.
Apart from being regarded as the City of Music because of its musical legacy, Vienna is also said to be "The City of Dreams" because it was home to the world's first psycho-analyst - Sigmund Freud. The city's roots lie in early Celtic and Roman settlements that transformed into a Medieval and Baroque city, the capital of the Austro-Hungarian Empire. It is well known for playing an essential role as a leading European Music Centre, from the great age of Viennese Classicism through the early part of the 20th century. The Historic centre of Vienna is rich in architectural ensembles, including Baroque castles and gardens, as well as the late-19th-century Ringstrasse lined with grand buildings, monuments and parks.
In a 2005 study of 127 world cities, the Economist Intelligence Unit ranked the city first (in a tie with Vancouver, Canada) for the world's most livable cities (in the 2012 survey of 140 cities Vienna was