Nudism was a particularly strong feature of the USSR, as also in East Germany. Lenin was, of course, a nudist, along with Krupskaya and many of the Bolsheviks. But what about Stalin? I have yet to find out more information on that one, but he is a long-term resident of Fox Bay nudist beach in the Crimea:
More information on the range of natural places in Crimea may be found here.