Discovery of Penicillin

On September 28, 1928, Alexander Fleming returned to his lab at St. Mary's Hospital (in London) to find that a mold (Penicillium notatum) had contaminated a petri dish and killed the surrounding staphylococcus bacteria.

This serendipitous discovery led to the development of penicillin, the world's first antibiotic, saving millions of lives and revolutionizing the treatment of infectious diseases. This discovery of the first antibiotic marked a turning point in human history and revolutionized medicine.