Why skyscrapers don't just crumple on impact

Modern skyscrapers are mostly air. If you ground up the Empire State Building into a fine powder, the resulting pile of dust would barely fill a fraction of the space the building occupies. This hollow nature is exactly why they don't shatter like glass when a plane hits them.

Instead of a solid stack of bricks, a skyscraper is essentially a giant steel sponge. When a massive impact severs the main support columns on one side, the building doesn't fall because it "realizes" the weight needs to go somewhere else.

This is thanks to a trick called redundancy. Engineers build the skyscraper as a "tube-within-a-tube." The outer walls act like a stiff soda can, while the inner core acts like a rigid straw. They are tied together by belt trusses—massive horizontal steel braces that look like a weightlifter’s belt cinched around the building’s waist.