Vienna (; German: , Austro-Bavarian: Wean) 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. 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.
Evidence of continuous habitation has been found since 500 BC, when the site of Vienna on the Danube River was settled by the Celts. In 15 BC, the Romans fortified the frontier city they called Vindobona to guard the empire against Germanic tribes to the north.
Close ties with other Celtic peoples continued through the ages. The Irish monk Saint Colman (or Koloman, Irish Colmán, derived from colm "dove") is buried in Melk Abbey and Saint Fergil (Virgil the Geometer) was Bishop of Salzburg for forty years, and twelfth-century monastic settlements were founded by Irish Benedictines. Evidence of these ties are still evident in Vienna's great Schottenstift monastery, once home to many Irish monks.
In 1440, Vienna became the resident city of the Habsburg dynasty. It eventually grew to become the de facto capital of the Holy Roman Empire (1483–1806) and a cultural centre for arts and science, music and fine cuisine. Hungary occupied the city between 1485–1490.
In the 16th and 17th centuries, the Ottoman armies were stopped twice outside Vienna (see Siege of Vienna, 1529 and Battle of Vienna, 1683). A plague epidemic ravaged Vienna in 1679, killing nearly a third of its population.
In 1804, during the Napoleonic wars, Vienna became the capital of the Austrian Empire and continued to play a major role in European and world politics, including hosting the 1814 Congress of Vienna. After the Austro-Hungarian Compromise of 1867, Vienna remained the capital of what was then the Austro-Hungarian Empire. The city was a centre of classical music, for which the title of the First Viennese School is sometimes applied.
During the latter half of the 19th century, the city developed what had previously been the bastions and glacis into the Ringstraße, a new boulevard surrounding the historical town and a major prestige project. Former suburbs were incorporated, and the city of Vienna grew dramatically. In 1918, after World War I, Vienna became capital of the Republic of German-Austria, and then in 1919 of the First Republic of Austria.
From the late 19th century to 1938, the city remained a centre of high culture and modernism. A world capital of music, the city played host to composers such as Brahms, Bruckner, Mahler and Richard Strauss. The city's cultural contributions in the first half of the 20th century included, among many, the Vienna Secession movement, psychoanalysis, the Second Viennese School, the architecture of Adolf Loos and the philosophy of Ludwig Wittgenstein and the Vienna Circle. In 1913, Adolf Hitler, Leon Trotsky, Joseph Tito, Sigmund Freud and Joseph Stalin all lived within a few miles of each other in central Vienna, with some of them being regulars at the same coffeehouses. Within Austria, Vienna was seen as a centre of socialist politics, for which it was sometimes referred to as "Red Vienna". The city was a stage to the Austrian Civil War of 1934, when Chancellor Engelbert Dollfuss sent the Austrian Army to shell civilian housing occupied by the socialist militia.
The Anschluss and World War II
In 1938, after a triumphant entry into Austria, Austrian-born Adolf Hitler spoke to the Austrian Germans from the balcony of the Neue Burg, a part of the Hofburg at the Heldenplatz. Between 1938 (after the Anschluss) and the end of the Second World War, Vienna lost its status as a capital to Berlin.
On 2 April 1945, the Soviets launched the Vienna Offensive against the Germans holding the city and besieged it. British and American air raids and artillery duels between the SS and Wehrmacht and the Red Army crippled infrastructure, such as tram services and water and power distribution, and destroyed or damaged thousands of public and private buildings. Vienna fell eleven days later. Austria was separated from Germany, and Vienna was restored as the republic's capital city, but the Soviet hold on the city remained until 1955.
After the war, Vienna was part of Soviet-occupied Eastern Austria until September, 1945. As in Berlin, Vienna in September, 1945 was divided into sectors by the four powers: the USA, the UK, France and the Soviet Union and supervised by an Allied Commission. The four-power occupation of Vienna differed in one key respect from that of Berlin: the central area of the city, known as the first district, constituted an international zone in which the four powers alternated control on a monthly basis. The control was policed by the four powers on a de facto day to day basis, the famous "four soldiers in a jeep" method. The Berlin Blockade of 1948 raised allied concerns that the Soviets might repeat the blockade in Vienna. The matter was raised in the UK House of Commons:
They put up barbed wire fences around the perimeter of West Berlin in 1953, but not in Vienna. By 1955, the Soviets, by signing the State Treaty, agreed to relinquish their occupation zones in Eastern Austria as well as their sector in Vienna. In exchange they required that Austria declare its permanent neutrality after the allied powers had left the country. Thus they ensured that Austria would not be a member of NATO and that NATO forces would therefore not have direct communications between Italy and West Germany.
The atmosphere of four-power Vienna is captured very well in Graham Greene's screenplay for the film The Third Man (1949). Later he adapted the screenplay as a novel and published it. Occupied Vienna is also colourfully depicted in the Philip Kerr novel, "A German Requiem."
Austrian State Treaty and afterwards
The four-power control of Vienna lasted until the Austrian State Treaty was signed in May 1955. That year, after years of reconstruction and restoration, the State Opera and the Burgtheater, both on the Ringstraße, reopened to the public. The Soviet Union signed the State Treaty only after having been provided with the political guarantee by the federal government to declare Austria's neutrality after the withdrawal of the allied troops. This law of neutrality, passed in late October 1955 (and not the State Treaty itself), ensured that modern Austria would align with neither NATO nor the Soviet bloc, and is considered one of the reasons for Austria's late entry into the European Union.
In the 1970s, Austrian Chancellor Bruno Kreisky inaugurated the Vienna International Centre, a new area of the city created to host international institutions. Vienna has regained much of its former international stature by hosting international organizations, such as the United Nations (United Nations Industrial Development Organization, United Nations Office at Vienna and United Nations Office on Drugs and Crime), the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, the International Atomic Energy Agency, the Organization of Petroleum Exporting Countries, and the Organization for Security and Cooperation in Europe and the United European Gastroenterology Federation.
Because of the industrialization and migration from other parts of the Empire, the population of Vienna increased sharply during its time as the capital of Austria-Hungary (1867–1918). In 1910, Vienna had more than two million inhabitants, and was the fourth largest city in Europe after London, Paris and Berlin. Around the start of the 20th century, Vienna (Czech Vídeň, Hungarian Bécs) was the city with the second-largest Czech population in the world (after Prague). At the height of the migration, about one-third of the Viennese population was of Slavic or Hungarian origin. After World War I, many Czechs and Hungarians returned to their ancestral countries, resulting in a decline in the Viennese population. After World War II, the Soviets used force to repatriate key workers of Czech and Hungarian origins to return to their ethnic homelands to further the Soviet bloc economy.
In 1923, there were 201,513 Jews living in Vienna, which had become the third-largest Jewish community in Europe. 65,000 Jewish people were deported and murdered in concentration camps by Nazi forces, approximately 130,000 fled.
By 2001, 16% of people living in Austria had nationalities other than Austrian, nearly half of whom were from former Yugoslavia. ; the next most numerous nationalities in Vienna were Turks (39,000; 2.5%), Poles (13,600; 0.9%) and Germans (12,700; 0.8%).
As of 2012, an official report from Statistics Austria showed that more than 660,000 (38.8%) of the Viennese population have full or partial migrant background, mostly from Czech Republic, Slovakia, Hungary, ex-Yugoslavia, Turkey and Germany.  This is reflected today in the telephone list of the city where there is an eclectic list of surnames.