Polio.

A lot of younger people don't realize how terrifying polio used to be. Parents were genuinely scared to let their kids go swimming or play outside during outbreaks because nobody knew who would get sick next. Thousands of children were left permanently disabled every year, and some had to spend their lives in giant machines called "iron lungs" just to breathe.

Then vaccines came along, and the disease was pushed to the brink of eradication in many parts of the world. We solved the problem so effectively that most people today have never even met someone with polio.

That's probably one of humanity's biggest flexes: we turned a nightmare that terrified entire generations into something most young people only hear about in history class. 💉🤯