The Spanish Flu Pandemic of 1918–1920

The Spanish Flu was an exceptionally deadly global influenza pandemic caused by the H1N1 influenza A virus. It infected an estimated 500 million people—nearly a third of the world's population at the time—and killed anywhere from 17 to 100 million, making it one of the deadliest pandemics in human history. Despite its name, the disease did not originate in Spain; the misnomer arose because Spain was neutral during World War I and its press freely reported on the outbreak while other nations censored the news.