Spanish Flu
"Spanish flu" is the name given to the Influenza pandemic that ravaged the world population between 1918 and 1920. This particular strain of Influenza is arguably believed to have originated in Fort Riley, Kansas before spreading throughout the planet. During that time it is believed to have affected approximately 500 million people leading to between 20 and 50 million fatalities. At first thought to have been a particularly powerful strain, this belief was downgraded by its association with WWI's concentration of soldiers in US military camps (that were heavily affected by the disease) that were later deployed to Europe. In Europe it spread through the weakened and malnourished populations. Interestingly, information about the spread of this disease through North America and the allied countries of western Europe was suppressed by news media. However, its spread through neutral Spain was not suppressed. As it was the alleged cause of the death of Spain's king Alfonso XIII, it came to be known as "Spanish" Flu.