Manhattan had long lost its crown as the world’s skyscraper capital when Mohamed Atta smashed American Airlines Flight 11 into the first of the Twin Towers. Yet that dramatic, appalling moment triggered a defiant reaction. A slew of new towers is now appearing, on screens and on the ground.

Renzo Piano’s diaphanously corporate New York Times Tower has just opened to rapturous reviews; Ground Zero is hosting towers by Foster, Rogers and Fumihiko Maki, and slick condo towers are springing up everywhere like minimalist fungus. But the latest proposal is by far the most surprising. French architect Jean Nouvel has proposed the most radical and striking skyscraper to trouble New York’s low-drifting clouds in a generation.