Construction on Citadel’s planned 350 Park Avenue skyscraper in Midtown Manhattan is moving forward despite billionaire ...

Antoni Gaudí's incredible unbuilt tower is a hotel, a cultural complex, a vertical city, and cathedral in one building.

How tall could we really build? After a century of competition, skyscrapers are reaching new extremes.

Frank Lloyd Wright's soaring unrealized tower would have been four times the height of the Empire State Building.