The miracle of Kevlar
Kevlar, the material that can stand up to a bullet, was developed by DuPont in 1965.
Kevlar is five times stronger than steel, but 5.5 times less dense, so it weighs much less.
It's actually a fiber with a density of 1.4 grams per cubic centimeter. Compare that to another strong material, iron, with 7.9 grams per cubic centimeter.
It is unaffected by extremes in heat and cold and only begins to decompose at 850 degrees Fahrenheit.
It is easily squashed, so it can't replace steel in buildings.
