Pictured above from Unrealized Moscow is the Palace of Soviets:
The competition for the Palace of Soviets in Moscow was one of the most extensive and impressive of this century. The idea of constructing a building which could be a symbol of the “imminent triumph of communism” in the capital of the world’s first state of workers and peasants was mooted in the 1920s. The chosen location was the site of the demolished Church of Christ the Saviour. The competition was launched in 1931 and carried out in stages.
(via Boing Boing)