In 1847, a Vienna doctor discovered that handwashing with chlorine could cut childbirth deaths by 90 percent, but the medical world refused to believe him

In a radical move, Ignaz Semmelweis mandated handwashing in hospitals, drastically reducing maternal mortality rates. Despite evidence supporting his approach, he faced fierce opposition from fellow medical professionals, as he couldn't provide a scientific rationale for his findings. Much later, the establishment of germ theory validated his revolutionary work, leading to fundamental changes in medical practices that ultimately saved innumerable lives.