Architecture has been very popular with car makers in recent years; one after the other they have embarked on high-visibility branding exercises. Mercedes Benz engaged UN Studio to design a Mercedes museum in Stuttgart, and in the same city Porsche is building a museum designed by Delugan Meissl. Meanwhile, in Paris, Citroen has just taken delivery of a new showroom on the Champs Elysées. With 'car architecture', as with the cars themselves, each new project looks bigger, more streamlined and faster than the one before. Coop Himmelb(l)au designed a spectacular steel and glass tornado for BMW World, 'a centre for brand experience and vehicle delivery'. The new building complements the striking four-cylinder head office (Karl Schwanzer, 1973) and the adjacent, shell-shaped BMW museum. Set on a corner plot, the double-conical structure with event room fans out into a sculptural roof beneath which the customer lounges are suspended in the main hall.