#4: Ignaz Semmelweis (July 1, 1818 – August 13, 1865)
Hungarian physician Ignaz Semmelweis became one of history’s most unfairly dismissed medical pioneers. While working at Vienna General Hospital in the 1840s, he discovered that handwashing with chlorinated lime dramatically reduced cases of puerperal fever, a deadly postpartum infection. Instead of accepting the evidence, many doctors rejected his findings and refused to believe they were spreading the disease since germ theory had not yet gained widespread acceptance. Today, hospitals around the world follow the same life-saving practice he championed.
