Skyscraper!
We’re so used to hearing that word, we don’t really think about it. Today we have airplanes. We’ve flown to the Moon. Scraping the sky doesn’t seem like such a big deal.
But go back to this date in 1884. Today the city issued a permit to build an office building at the northeast corner of La Salle and Adams. The Home Insurance Building would become the world’s first skyscraper. It would start a revolution.
Before 1884 buildings were supported by their walls. The higher you went, the wider the bottom. That’s because the base had to support the weight of everything above it. Think of the pyramids.
Of course, you could take some of the weight off the walls by putting support columns inside the building. Trouble was, you reduced interior space, and wound up with a bunch of small rooms.
And because your outside walls were weight-bearing, glass windows had to be small. That limited the sunlight coming into your building. You want larger windows? Then you build buttresses holding up your walls, like the Gothic cathedrals.
William LeBaron Jenney, architect of the Home Insurance Building, changed this. Metals had become easier to use and stronger. Jenney built an interior metal frame as the main support of his building.
Most of the frame was iron. But Jenney also used steel, making Home Insurance the first building to use structural steel in its frame. The 10-story structure topped off at 138 feet in 1885.
Jenny’s building was not totally supported by the metal frame. Home Insurance is important because it showed the way of the future. That’s why it is called the world’s first skyscraper.
William LeBaron Jenney
Now other architects began going higher and higher. Windows were made bigger and bigger. Compared to older structures, the walls of the new buildings looked like curtains of glass. This was the so-called Chicago School of Architecture.
About this same time, electricity was being harnessed. That was vital. The new power source made construction easier. And once the building was completed, electricity ran the elevators and provided the lighting.
The Home Insurance Building added two additional floors in 1890. By then it was already being dwarfed by other nearby construction. In 1931 Chicago’s pioneer skyscraper was demolished—to make way for a taller building.
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Chicago History Today 
Very cool!