Discovery of Penicillin
Alexander Fleming discovered penicillin, leading to the development of antibiotics that would save millions of lives.
On September 28, 1928, Scottish bacteriologist Alexander Fleming noticed that a mold colony (Penicillium notatum) had contaminated a petri dish of Staphylococcus bacteria and was killing the surrounding bacterial colonies. This accidental discovery led to the development of penicillin, the world's first widely used antibiotic. Mass production during World War II saved countless lives, and antibiotics have since prevented hundreds of millions of deaths from bacterial infections.
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The Plague of Athens
A devastating epidemic struck Athens during the Peloponnesian War, killing an estimated quarter of the population including Pericles, and undermining Athenian democracy at its peak.
~165 CEThe Antonine Plague
A devastating pandemic — likely smallpox — swept through the Roman Empire, killing an estimated 5 million people and weakening Rome's military and economic foundations.
October 1347Black Death Reaches Europe
The bubonic plague pandemic arrived in Europe, eventually killing an estimated 30-60% of the European population.
~1520Smallpox Devastates the Americas
European colonizers brought smallpox to the Americas, killing an estimated 90% of the Indigenous population and enabling the rapid conquest of vast civilizations.