A short walk from the Kremlin, the Shchusev State Museum of Architecture is a haunted place. Paint is peeling off the once-elegant neo-Classical facade. An entire wing of the complex of 17th- and 18th-century buildings is partly abandoned -- because they're too expensive to heat during the long Russian winter. Yet the museum contains one of the world's best collections of architectural artifacts: everything from an elaborate model of a palace once planned for Catherine the Great to Ivan Leonidov's mythic drawings for the People's Commissariat of Heavy Industry. (Had the latter been built, it would have towered above Red Square.) In many ways, these archives represent the city's architectural conscience, a treasury of what Moscow lost and what it could have been during one of the more violent centuries in Russian history.
Along with an audio slide show of some amazing images
(I believe you have to register to view this, but it's free and well worth it)