On this day in 1954,

THE SALK POLIO VACCINE TRIALS

"The Greatest Public Health Experiment in American History."

There was a terrifying polio epidemic going on.  Parents were worried that their kids might be infected with crippling and incurable polio, that they may never walk again, and that they might even die.  Then this.  A discovery that changed life for the better for millions.

Great background story here from CBS News:

www.cbsnews.com/news/the-salk-polio-vaccine-greatest-public-health-experiment-in-history/