Alexander Fleming's 1928 Lab Accident Led to the Discovery of Penicillin

In 1928, Alexander Fleming was working at St. Mary's Hospital in London when he returned from a holiday to find that a stray mold had contaminated one of his Petri dishes. The mold, later identified as Penicillium notatum, had killed the Staphylococcus aureus bacteria surrounding it. This observation led Fleming to realize the mold's antibacterial properties, which eventually resulted in the development of penicillin, the world's first antibiotic.