//
Museum of public transport (formerly known as Straßenbahnmuseum / Streetcar Museum)
Photo: Jacek Rużyczka, CC BY-SA 3.0 via Wikimedia Commons
This museum in a former depot houses a comprehensive collection of vintage vehicles explaining the history of Viennese public transport. The exhibits include horse-drawn streetcars from 1868, a steam tram set from 1885, many electric streetcars from the 1910s until the recent past, and buses from 1949-1978, including the infamous "Reichsbrücken-Bus" which fell into the Danube but was recovered and repaired to run for many more years. The simulator of a U-Bahn train is considered the highlight among guests. Attached small gift shop. Major labels are in English and German, but some smaller items are labelled in German only.
© OpenStreetMap contributors
Arena Wien
The arena is one of the biggest concert and alternative culture places. The slaughterhouse got squatted in 1976 and operates since as culture center. FM4 hosts here its annual birthday party. The programme lists the performing artists. The open air arena can host 3000 peoples.
Interesting apartment/office complex, designed by the Austrian architect/painter Hundertwasser. Remember that most of it is still in use as housing or offices and respect the residents' privacy. The nearby KunstHausWien (see above) is a Hundertwasser building you can freely explore.
Museum of Art Fakes
Unique museum devoted to art forgery. Houses a large collection of counterfeited paintings, many from highly-skilled, infamous forgers. Includes several pages of the infamous fake Hitler diaries which fooled numerous experts in the early 1980s.
St. Marx Cemetery
This historic cemetery was in use from 1784 until 1874. Mozart was buried here in an unmarked pauper's grave in 1791; the tombstone dates from a later period, after his grave was tentatively identified. The Bezirksmuseum Landstraße offers regular guided tours of the cemetery (in German).
Botanic Gardens
Established in 1754 by Empress Maria Theresia as a garden for medicinal plants and granted to the University of Vienna, which has maintained it since. The gardens contain a number of rare plants, including alpine specimens.
Vienna House of the Arts
Even an avowed hater of modern art can appreciate this. This is Hundertwasser's (born Friedrich Stowasser in 1928) major contribution to the Viennese art world. In a time when artists often try to shock the public or merely impress other members of the rarefied gallery subculture, Hundertwasser's KunstHausWien would be a bastion against the dictatorship of the straight line, the ruler and T-square, a bridgehead against the grid system and the chaos of the absurd. Starting with the façade of the building, adapted from its prior life as a furniture factory, there is a Gaudi-in-Barcelona feel to the place. Windows peek out like eyes from curvy, rounded plaster and colorful paint. It is a Disneyland for grownups.