In 1956, architect Frank Lloyd Wright proposed a mile-high skyscraper.
It was going to be the world's tallest building, by a lot — five times as high as the Eiffel Tower.
But many critics laughed at the architect, arguing that people would have to wait hours for an elevator, or worse, that the tower would collapse under its own weight.
Most engineers agreed, and despite the publicity around the proposal, the titanic tower was never built.
But today, bigger and bigger buildings are going up around the world.
Firms are even planning skyscrapers more than a kilometer tall, like the Jeddah Tower in Saudi Arabia, three times the size of the Eiffel Tower.
Very soon, Wright's mile-high miracle may be a reality.
So what exactly was stopping us from building these megastructures 70 years ago, and how do we build something a mile high today?
In any construction project, each story of the structure needs to be able to support the stories on top of it.
The higher we build, the higher the gravitational pressure from the upper stories on the lower ones.
