A temporary emergency hospital in Camp Funston, Kansas, during the 1918–19 influenza pandemic.
Despite its name, it is most likely that the flu originated in Haskell County, Kansas, in January 1918. Farmers raised hogs in Haskell County, which falls under a migratory flyway for over a dozen species of birds. A possible source of the flu was both a human virus and a bird virus infecting a single pig cell.
To learn more about the possible origin of the Spanish flu, see the Smithsonian's video:
(Click images for more information)