The USSR wasn't all purges, executions and bread queues: there was an optimistic side to the People's Revolution (see also Spufford's novel Red Plenty, though admittedly it was submerged in grey concrete and misery for long periods (thanks to Stalin's perversion of Communism, but that's a rant for another day). Modernism and progressive politics once went hand-in-hand, until lack of money and imagination, coupled with poor-quality materials, produced the horrid hutches beloved both of East German commissars and British municipal housing officers. But there was a window in which People's Palaces and amenities were made with the very latest materials (to show how modern the USSR was), which meant concrete, allowing buildings to branch out, swoop and swerve. What a shame that concrete ages so badly and the building standards weren't great. But the architecture was often magnificent.
Here's the Druzhba Sanatorium in Ukraine - once mistaken by the Pentagon for a launch-pad: rooms now available.