Palace of the Soviets
Both Hitler and Stalin planned, but never completed, enormous domed assembly halls as part of their efforts to establish global capital cities. Hitler's Volkshalle, or "People's Hall", was meant to have a dome 250 meters wide and hold 200,000 people. The Palace of the Soviets in Moscow was meant to be the tallest building in the world, rising above a domed congress hall 100 meters wide for 21,000 world socialist delegates. The foundations were begun for the Palace of the Soviets on the site of the demolished Cathedral of Christ the Saviour, but technical problems postponed the project and it was abandoned after Stalin's death in the 1950s. R. J. Overy writes that these were meant to be monuments to dictatorship and utopian civilization that would last for ages.