#34: Vaccinations
Some of the most important discoveries we have ever made came about simply through good luck. Vaccines are one of the most incredible advances of recent centuries, allowing us to avoid illnesses that used to incapacitate, disfigure, and kill vast portions of the population. And it was luck that the first one was developed!
In the 1700s, a doctor named Edward Jenner happened to be treating people who worked with cattle for smallpox and noticed that their symptoms were much milder than those of many other people. He realized that because they worked with cows, they had been exposed to the related disease, cowpox. This led to the realization that a minor, controlled exposure to certain viruses could protect you from getting the full force of the illness in the future.