Vienna's Art Nouveau Architecture Tour I (Self Guided), Vienna

A relatively recent addition to the city's architectural heritage, the Hundertwasserhaus is a great example of 20th-century urban experimentation and certainly one of Vienna's top tourist attractions. Sitting as an antithetical statement about what architecture can be (as it's often compared to the surrounding buildings), this gloriously eclectic block of flats can almost look like a rainbow from afar, consisting of a frenzy of oriel windows, loggias, shiny ceramic pillars, glass embellishments, a gilded onion dome, roof gardens and even a slice of the pre-1983 building. There's simply nothing else like it in the city.

The idiosyncratic housing development was created in 1985 by avant-garde artist Friedensreich Hundertwasser, who wished to diverge from what he perceived as the rather soulless modern architecture emerging in Vienna's suburbs. The result was a structure that has been controversial since its construction – but further to his credit, Hundertwasser took no payment for the design, declaring that the investment was worth it to "prevent something ugly from going up in its place".

Why You Should Visit:
To marvel at an expression of sheer architectural exuberance that stands in contrast to the stately palaces (and pretty much everything else).

Tip:
As a private building it is closed to the public, but opposite is the Hundertwasser Village (9am–6pm daily) designed by the same artist – a bazaar of shops and cafés open to the public, and a pleasant place to peruse for quirky souvenirs.

KunstHausWien, housed in a former furniture factory and opened to the public in 1991 as a museum, is another of Hundertwasser's Gaudí-esque conversions, exhibiting the largest collection of the eccentric artist's paintings, printed graphics, tapestries and architectural designs. Vienna's first "green museum" also gives its visitors the chance to experience Hundertwasser's visionary ecological commitment – he experimented with grass roofs and planted trees in building façades. Over and above this, the KunstHaus is Vienna's premier house for photo exhibitions, particularly those focused on street photography. Audio guides are provided for a small fee.

Colorful and bizarre, the building itself is pure Hundertwasser and recommended for everyone wanting to escape Baroque, with its irregular floors, trees growing out of windows, and sudden architectural surprises, all of which make a wholly appropriate setting for modern art. Makes you wonder if Hundertwasser and Gaudí were friends!

Tip:
Check out the lovely café at the back with a terrace that just waits for you to take a seat and relax. There's also a shop nearby so you can buy a memento of the visit.

Opening Hours:
Daily: 10am–6pm

Once Vienna's first public observatory cum adult education center hosting courses/lectures by leading intellectuals of the time (including Albert Einstein and Thomas Mann), the multi-purpose Urania has over the years branched into a cinema, a large planetarium, a modern café-bar, and also – of all things – a puppet theater. That is quite the mix of things for one small place!

Designed by Max Fabiani, who studied under the famous Otto Wagner, the Art Nouveau-style structure was built in the shape of an unorthodox ship in 1910 and named after the famous muse of astronomy. It sits very close to the Danube, in a very scenic part of town, with the café-bar's fabulous elevated terrace overlooking the canal.

During the Second World War, Urania was severely damaged, and the observatory was rendered completely useless. Thanks to some generous patrons, however, the location was reopened, providing incredible views of the heavens in addition to one of the most beautiful panoramas of Vienna. Take advantage of your visit by observing it from the other side of the river and from the nearby bridge, and you'll agree that it is definitely one of Central Europe's most remarkable buildings.

Opening Hours:
[Observatory guided tours] Tue: 9pm, Sat: 5pm/9pm (Apr-Sep); Tue: 8pm; Sat: 5pm/8pm (Oct-Mar)
[Planetarium] Tue-Sun, hours vary; [KLYO café-bar-restaurant] Daily: 9am–1am

The Postsparkasse building in Vienna, built by Otto Wagner in 1903, revolutionized architecture in Vienna. An early example of a building done with a steel grid system, and then reinforced with concrete, this type of construction is now done the world over, and is considered pretty much standard fair; however, in the early 1900s, the secessionist design and choice of materials were – and still are – considered a marvel to behold. You need only compare it with the nearby structures, especially the pompous ministry building at the other end of the park, to feel what a revolution this must have been.

The building's clear lines and cool elegance, achieved by the usage of steel, concrete and glass, give it a solid and impenetrable look. The skylight in the main hall nevertheless allows for natural light to reach the interior of the building, making it light and airy at the same time.

On weekdays, you can explore the back section of the building which houses a museum (entrance is free) dedicated to Otto Wagner and his building, along with various temporary exhibitions on design. There's a good documentary (in German only) about Wagner's life and work, detailing how he designed everything in the Postsparkasse – even down to the chairs and tables used. And it's all there to see, along with plans. Well worth a visit.

Opening Hours:
Mon-Fri: 10am–5pm

Named after the Anker Insurance Company, which financed it, this early 20th-century Art Nouveau masterpiece set atop the Uhrbrücke or "Clock Bridge" between two buildings, is the work of Franz von Matsch, a close associate of renowned Austrian artist Gustav Klimt.

People flock here at noon when the clock puts on a show, with twelve historical figures slowly stagger across the clock face. These include Marcus Aurelius (the Roman emperor who died in Vienna in AD 180), Empress Maria Theresa, Joseph Haydn, and other (details of who’s who are on a street-level plaque), each one accompanied by music from their era. The tunes, including works by Mozart and Wagner, were originally played by a mechanical organ containing an incredible 800 tubes, which managed to survive the WWII artillery fire, but was damaged to such an extent that it could not be repaired and was replaced by a ten-minute medley of digital sound reproduction.

It's not an overly big deal like the Astronomical Clock in Prague (which happens to be similarly fitted with twelve gilded figures and similarly built in green and gold colors), but it's fun to see, and you are not getting crushed by crowds of tourists the way you might in Prague.

Tip:
Another interesting monument to view at Hoher Markt is the attractive Baroque-style "Marriage Fountain" (Vermählungsbrunnen) that dates back to the mid 18th-century.

Placing a modern style edifice directly opposite the Gothic Stephansdom (St. Stephen's Cathedral) was a difficult task with which the city entrusted one of Austria's leading Postmodernist architects, Hans Hollein, author of several uncompromising jewelry stores along der Graben and Kohlmarkt streets, each of which is a minor masterpiece in its own right. The result was the iconic 1990 Haas Haus, a shining, partly mirrored structure of glass, steel and blue-green marble that curves elegantly into the street, successfully blending into the colors, shapes, and grandeur of downtown Vienna.

The building looks pleasingly asymmetrical, replete with decorative elements, such as lopsided cubes of marble attached to the facade, a protruding structure high up resembling a diving board, and a Japanese-style bridge inside. The architecture proved an intelligent alternative to the demands of Historicism on the one hand and aggressive modernism on the other, presenting a futuristic, respectful challenge to the nearby Cathedral's soaring spires, reflected in the mirrored facade. Along with the office spaces, the Haas Haus atrium accommodates cafes, shops, a restaurant, and the upmarket DO & CO Hotel.

Tip:
Take a ride to the top of the building to check out the coffee house, and enjoy the view of the old Cathedral with a nice cup of coffee in hand.
Alternatively, visit the HAAS & HAAS TEAHOUSE (Mon-Sat: 8am–8pm; Sun/Holidays: 9am–6pm) located just outside the Cathedral.

Designed by Adolf Loos and erected in 1910-12 on imposing Michaelerplatz, this building so outraged the Emperor Franz Joseph, who lived across the road, that he not only avoided it for the rest of his life, but also ordered the curtains of his windows to remain permanently shut. The source of the emperor's indignation was the starkly functional upper façade, which contrasts dramatically with the imperial square's ornate Baroque exuberance. The Viennese called it "the house without eyebrows", since the usual window roofing/detail was missing entirely. Work was allowed to continue only after Loos agreed to add the 10 bronze flower boxes adorning the façade today.

Despite its aesthetic functionalism, the building is not as merely functional as it may seem – especially in the materials used for the ground floor (Cipollino and Skyros marble) and the Tuscan columns on street level, intended as an allusion to the portico of St. Michael's Church. The interior decoration remains a breathtaking surprise, having been restored and brought as close as possible to its original condition, with no fear of cost. Because the building now houses a bank, one can only 'tour' the ground floor exhibition of its history, and gaze wistfully at the magnificent wooden staircase.

Tip:
To really get up close and personal with Adolf Loos, head to the splendor of his LOOS AMERICAN BAR (12pm–4am daily), about six blocks east at No. 10 Kärntner Durchgang. Come have a classic cocktail as they were crafted over a century ago; stay for the ambiance and the design.

Opening Hours:
Mon-Wed, Fri: 9am–3pm; Thu: 9am–5:30pm