IN SEPTEMBER 2001, New York developer Donald Trump was dreaming of building the world's tallest skyscraper, a 2,000-foot mega-tower that would return the record to America from Malaysia, where it had been lost, though not without controversy, to the twin Petronas Towers. Trump's people met in Chicago with architects from the legendary firm Skidmore, Owings and Merrill, which had designed the magnificent John Hancock Center in that city, with its bridge-like exoskeletal steel ribs, and the Sears Tower, which had been dethroned by Petronas in 1996. What Trump and his collaborators imagined would have dwarfed them all: 200 stories, a stab at the heavens.
Then, news. During the Chicago meeting someone switched on a television. A plane had crashed into the World Trade Center in New York. "We watched as another plane hit, and then had to evacuate our building," recalls architect Adrian Smith. "Later, Trump's people called and said they didn't want to build the tallest building anymore. They didn't want to be a target."
September 11 marked the end of an architectural era, if you believed the gloomy speculation. "Skyscrapers took a hit everywhere," sighs Eugene Kohn, president of Kohn Pedersen Fox Associates (KPF), one of the world's largest architectural firms. Critics of the WTC pointed out that buildings taller than 80 stories aren't economically justifiable anyway. And how could the safety of occupants be guaranteed against devastating attack? As structural engineer Ron Klemencic notes: "It may be generations before America returns to skyscrapers."
Not so fast.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.