City Hall on Thursday unveiled five dramatically futuristic designs for the planned global terminal at O’Hare Airport.

The superstar architects being considered for the $8.5 billion project include Chicago’s own Jeanne Gang, as well as Santiago Calatrava, whose Milwaukee Art Museum has drawn rave reviews. Calatrava is perhaps better known here as the designer of the Spire, a corkscrew-like supertall tower that was never built.

The designs, though quite different, all feature swooping or gently undulating rooflines and vast spaces flooded with sunlight.

The mayor’s plan calls for demolishing Terminal 2 and replacing it with a new “global terminal” shared by United and American that would accept both domestic and international flights. O’Hare would become the first so-called “global alliance hub” in the nation. It will allow domestic airlines and the international carriers they partner with to be in the same terminal — and that means passengers connecting to international flights will avoid the delay and inconvenience of riding the O’Hare people mover to the international terminal.

The new terminal is expected to open in 2028.

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