In Frank Lloyd Wright’s 1957 book, A Testament, he presented his visionary skyscraper that was to be over one mile high. Known as The Mile High Illinois, Illinois Sky-City, or simply The Illinois … if built, it would top the list of the tallest building in the world by far, being more than four times the height of the Empire State Building, and twice as tall as the world's current tallest building, the Burj Khalifa, the design of which is said to have been inspired by that of The Illinois.
Wright intended the building to be built in Chicago, and would have included 528 stories, with a gross area of 18,460,000 square feet. Wright stated that there would have been parking for 15,000 cars and 100 helicopters.
He wanted 76 elevators, each having five-floor-high tandem cabs, serving blocks of five floors simultaneously. The 76 elevators would be divided into five banks or groups, with each elevator group serving a hundred-floor segment of the building. The elevators were to be “atomic powered,” capable of mile-per-minute speeds, and running on ratchets instead of suspended by cables. The elevator banks extend beyond the sloping exterior walls at various points, giving the building the appearance of an elongated pyramid with protruding parapets. Wright said these elevators would enable the building to be evacuated in one hour, in combination with escalators that would serve the five lowest floors. The floor plan for the 320th floor shows a single, open staircase, not separated from the surrounding office space in any way, not even with a door. The floor plan of the 528th floor shows that access is solely by a single elevator, with no staircase at all. Wright believed that because his building was fireproof, any fire precautions would be moot.