History loves a good joke. The St. Petersburg mansion belonging to the Russian prima ballerina Mathilde Kschessinska (of Polish origin) who was a mistress of Tsar Nicholas II got ransacked and pillaged during the Russian Revolution in 1917 and became Lenin's headquarters. Lenin addressed the masses from the balcony of a prima ballerina.
I DID NOT KNOW THIS CURIOUS HISTORICAL FACT. It made me snort my coffee.
More blueprints, drawings, and photos of the mansion here.