Cities will change in the future

Gregory Benford : science fiction author and astrophysicist
Cross section of the future city, with many traffic levels underground; top, street for pedestrians only, and airplane landing fields, above. “The step-back skyscrapers of the future will have moving stairs on the outside of the buildings instead of elevators, with facilities for passengers to alight at any floor,” declared Harvey Wiley Corbett, noted city planner. “Some of the skyscrapers will be a half mile high and will house small-sized cities.”Major Henry H. Curran of New York, opposes Mr. Corbett and points to the impossibilities of such buildings in terms of human happiness as well as construction, saying, “There are everyday workers who count their ribs on release from the elevators and subways that take them to their offices. They must pop out of kiosks like prairie dogs.”
The tallest building in today’s world is Burj Khalifa in Khalifa. At 2,684 feet, it’s just over a half mile high, although its use is primarily commercial and it lacks the moving stairs.

GREGORY BENFORD, Popular Mechanics, (2012), "The Future That Never Was: Pictures from the Past', [online], Available: