Short answers, pulled from the story.
Vienna is the capital and most populous city of Austria, with just over two million inhabitants in the city proper. Its larger metropolitan area has a population of nearly 2.9 million, representing nearly one-third of Austria's total population.
The Romans called the settlement Vindobona. Construction of the legionary camp began around AD 97, positioned in the province of Pannonia to defend the empire's frontier along the Danube. Roman emperor Marcus Aurelius may have died there in AD 180.
Red Vienna refers to the period from 1919 to 1934 when Social Democrats governed Vienna with an absolute majority. Between 1925 and 1934, the city built over 60,000 new apartments in public housing complexes called Gemeindebauten. The programme ended after the Austrian Armed Forces shelled the Karl-Marx-Hof during a civil war in 1934.
Of the nearly 200,000 Jews living in Vienna before the Anschluss, approximately 120,000 were driven to emigrate and around 65,000 were killed. After the war, Vienna's Jewish population was only about 5,000. All synagogues and prayer houses in the city were destroyed during Kristallnacht, except for the Stadttempel.
Composers born in Vienna include Franz Schubert, Arnold Schoenberg, Alban Berg, Anton Webern, and Johann Strauss I and II. Many others relocated there to work, including Joseph Haydn, Wolfgang Amadeus Mozart, Ludwig van Beethoven, Johannes Brahms, Gustav Mahler, and Antonio Salieri.
From September 1945 until July 1955, Vienna was divided into sectors controlled by the United States, the United Kingdom, France, and the Soviet Union. The central first district rotated between the four powers each month. The occupation ended when the Austrian State Treaty came into force on the 27th of July 1955.