The big idea
A skyscraper is a stack of floors held up by a skeleton, not by its walls. Deep piles and a raft carry its weight into the ground. A stiff core and big columns, tied together by outriggers, carry the weight down and stand up to the wind. A light glass curtain is hung on the outside, lifts run up the middle in zones, and protected stairs give a way out. At the top, a damper can calm the sway.
Memory trick: “Piles below, core inside, frame around, glass outside, lifts up the middle, damper at the top.”
A bit of history: Tall buildings became practical in the 1850s to 1880s, when the safety elevator (Elisha Otis, shown in 1854) and the metal frame came together. Chicago and New York led the way: the Home Insurance Building in Chicago (1885) is often called the first skyscraper, and New York's towers held the height record from 1908 into the 1970s. Since then the record has moved to Chicago, Kuala Lumpur, Taipei and, in 2010, to Dubai, where Burj Khalifa stands 828 m tall.
In a fire, people in a tall tower are told to make for the protected stairs and refuge floors, built to keep them safe. An old proverb uses the same picture: The name of the LORD is a strong tower: the righteous runneth into it, and is safe.
(Proverbs 18:10, KJV)