Loos American Bar

For fans of architecture, the Loos Bar is a must while in Vienna. Adolf Loos, one of the first modern architects in history, is best-known for his infamous Looshaus (1910-12), a provocatively undecorated building that outraged the Habsburg royal court living across the street from it on Michaelerplatz.

The American Bar (1907), hidden on a downtown side street off Kärntner Straße, embodies the stylistic philosophy of Loos: exquisite materials – marble, mahogany, alabaster – without superfluous decorations. The dim cocktail bar is tiny, the impact is striking (lots of mirrors are meant to enlarge the space). That portrait hanging on the wall: he's Peter Altenberg, a close friend of Loos and a famous Viennese coffeehouse poet.

The crowd is heavy on tourists and scoring one of the few precious seats is nearly impossible, but a visit is worth it for a peek at least. Try going during off-hours.