Eugene Tsui's design for a two-mile high, one-mile wide eco-topian tower that houses one million people and contains its own ecosystems seems like something out of a Robert Silverberg novel. But Tsui is dead serious -- and he's got the architectural chops to make it happen.

It's not so much a building, Tsui says, it's a living environment. A vertical train will take people from the ground floor to the top in about 10 minutes.