The 1918 Spanish Flu Pandemic: Origins, Spread, and Impact

The 1918–1920 Spanish flu pandemic infected ~500 million people (one-third of the world's population) and killed an estimated 20–50 million, making it one of history's deadliest pandemics.

Name origin: "Spanish flu" is a misnomer. Wartime censorship in Allied nations suppressed outbreak news, while neutral Spain reported freely, creating a false impression that Spain was hardest hit. The true geographic origin remains undetermined.