Discovery Channel has an interactive feature on Tokyo's super-ambitious Sky City. It is the most massive building ever envisaged, with 14 steel, glass and concrete 'plateaus' stacked on top of each other. The structure would rise a mile into the sky and house some 35,000 people.
Other unbelievable features of the Sky City include schools, offices, shops, green parks on each plateau, a monorail that would ferry 100,000 people through the massive structure during rush hour, possibly a small airport alongwith heliports, super express elevators that go up 3,300 feet in just over 2 minutes and even an Olympic-sized sports and entertainment stadium suspended between the three towers of the structure!!
The only hitch that the engineers from Japan, Taiwan and Canada are facing are the ways to protect this gargantuan structure from earthquakes, typhoons, raging infernos, etc.