 The Spanish flu pandemic of 1918 was one of the most devastating pandemics in history, resulting in the deaths of over 50 million people worldwide. Despite advances in medical technology and knowledge since then, there are still many unknowns regarding the origin, pathology, and transmission of this virus. Recent research has revealed more details about the virus, such as its complete genetic sequence, but further investigation is needed to fully understand the pandemic's implications for future outbreaks. This article was authored by Jeffrey K. Taubenberger and David M. Morins.