AT THE CENTER of the Venn Diagram of Brutalist architecture, spa culture and Communist kitsch lies the Soviet sanatorium. In its heyday, the USSR had a network of hundreds of such centers across dozens of territories, from Estonia to Kazakhstan to the Russian Far East. Though their roots lie in the Russian tradition of curative baths, the sanatoriums of the 20th century shoehorned nicely into Soviet ideals of health and responsible rejuvenation, with workers encouraged to check themselves in yearly for a tune-up of their corporal machinery.