The Spanish Flu, which started during WWI,  got the name as the result of a misunderstanding. Spain was hit hard by the epidemic – and though other major European countries and the US suppressed the news to avoid affecting morale, the press in Spain (one of the few countries to remain neutral during the war) reported on it in all its gory details. Since the only in-depth information was coming from Spain, people in other parts of the world assumed that Spain was ground-zero. Meanwhile, the Spanish, believing the virus had spread to them from France, were calling it the French Flu. (Source: History.com)