It pays to show up early because this tiny American Bar, designed in 1908 by Adolf Loos, gets crowded in a hurry—it magically attracts travelers and Viennese who love design. The famous architect used materials such as onyx, marble, wood, and brass in the interior; cleverly placed mirrors gives this architectural gem a feeling of space. Yet watch your step when you descend into the basement: The stairs are steep, and visitors need to be careful especially after having enjoyed a drink or two.