What’s a massive human achievement that is often unappreciated?

What’s a massive human achievement that is often unappreciated?

Toilets. Do I have to say more?
— Eridium_Purple

I believe soap is widely considered the biggest invention in history, changed hygiene forever
— TheAlgerianAmerican

Language itself is incredible. We've managed to take a little over 2 dozen symbols and made them capable of defining the entire known world. Really, if we could call anything "mind reading", it's the written language. The ability to communicate thoughts with individuals on the other side of the planet, or 500 years into the future. Crazy.
— ImBruceWillis

plumbing.. go camping for a few weeks and wow you appreciate the modern miracle of hot water ON DEMAND!
— wastingtoomuchthyme

Penicillin.
— HateHater77

Plumbing and modern sewer systems.
— LanguineO

Vaccines, here in the US we argue over whether they cause autism (they don't), in other countries you see how these various diseases have a huge impact on the population. Even places where polio has be eradicated you can still see it's effects on older members of the population.
— Sorce291

Writing. It's bloody convenient. Indeed, I'm writing right now. Remarkably efficient way of conveying thoughts.
— yellowsaxifrage

Grace Hopper. She invented the compiler which is the tool computer programmers use to turn their code into software. She was told computers were for doing calculations and not for running programs, so it couldn't be done. She figured it out anyway and changed the world forever. She might be the most important woman of all time. Nobody knows who she is.
— Paloma_Dominique

Melting rocks into more usable materials, i.e. making steel for tools and machinery, copper for wires, etc
— ItsUnderSocr8tes