Design for world’s first 1km-tall skyscraper unveiled

The competition to design a new skyscraper in Saudi Arabia had a simple but lofty rule: The tower had to be the world's first kilometer-tall building.

The design submitted by Chicago architects Adrian Smith and Gordon Gill — a sleek glass tower built atop three legs and tapering into a skyscraping needle — was announced as the winner Tuesday, further cementing Chicago's role as a hub of cutting-edge architecture.

Construction of the $1.2 billion building, called Kingdom Tower, is expected to begin around December in the waterfront city of Jeddah and be completed a little more than five years later, Smith said. The tower's exact height hasn't been revealed, but it will be the first building to be at least a kilometer, or 3,280 feet, tall, according to Adrian Smith + Gordon Gill Architecture.

Full story.