Vienna is the capital and largest city of Austria, and one of the nine states of Austria. Vienna is Austria's primary city, with a population of about 1.757 million (2.4 million within the metropolitan area, more than 20% of Austria's population), and its cultural, economic, and political centre. It is the 7th-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 only to Berlin in German speakers. 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 having played 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, and 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 ranked number two, behind Melbourne). For four consecutive years (2009–2012), the human-resource-consulting firm Mercer ranked Vienna first in its annual "Quality of Living" survey of hundreds of cities around the world, a title the city has reclaimed in 2014. Monocle's 2012 "Quality of Life Survey" ranked Vienna fourth on a list of the top 25 cities in the world "to make a base within" (up from sixth in 2011 and eighth in 2010).
The city was ranked 1st globally for its culture of innovation in 2007 and 2008, and fifth globally (out of 256 cities) in the 2011 Innovation Cities Index, which analyzed 162 indicators in covering three areas: culture, infrastructure and markets. Vienna regularly hosts urban planning conferences and is often used as a case study by urban planners.
Each year since 2005, Vienna has been the world's number one destination for international congresses and conventions. It attracts about five million tourists a year.