It’s so tiny that your living room seems spacious in comparison. On a side street off the lustrous Kärntner Strasse, the Loos American Bar was hypermodern back when it opened in 1908 as the Kärntner Bar with a design aesthetic that contrasted with what was standard then during the last days of imperial Vienna. Architect of Prague’s famous 1928 Villa Müller, Adolf Loos used mirrors to expand the mahogany, brass, and onyx interior. Outside, an American flag mosaic pops out from above the entrance and marble pillars. After years of decline, the bar was resurrected by new owners in the 1990s to once again become a landmarked shrine to modernism. The martinis and Manhattans served here are vintage American as well.