The story of vaccine is such a good story. Vaccine comes from the Latin word for cow 'vacca.' Why? The first vaccine was created by Edward Jenner. He observed that milkmaids were less likely to catch smallpox. What was it about the milkmaids that made them less susceptible to smallpox? The milkmaids were exposed to cowpox, a similar virus. He rationalized that exposure to the more benign cowpox was protective against the deadlier smallpox. So, he isolated the cowpox virus (vaccinia), injected it into people, and for the first time, people were vaccinated. All thanks to the cow. We don't call it being 'Jennered.' You're vaccinated.
There are other good stories in medicine. Pasteur was discovering germs. Lister was cleaning his surgical instruments. Beyond being good stories though, it's useful to remember their contribution to medicine. Their amazing discoveries are now barely worth mentioning in medical school because they are so self-evident, but that is the sign of a great discovery. It's right under our noses. It's also a good reminder that our current safe boundaries were once unknown frontiers.