Subways aren't the first things that jump to mind in a discussion of beauty. But there are plenty of breathtaking underground stations - usually of a futuristic bent. Moscow's 1930s subway stations have to be the most ostentatious stopping places in the world. Decked out with the huge chandeliers, vaulted plaster-moulded ceilings, arches and hand-painted frescoes of a state ballroom, expects commuters to break into a spontaneous waltz.