The Great Chicago Fire of 1871 started when Mrs O'Leary's cow kicked over a lantern in the barn, igniting the hay and then the city. For 150 years the cow has worn the blame, a tidy origin for one of the worst urban disasters in American history.
The cow was a journalist's invention. The fire did start in or near the O'Leary barn on DeKoven Street, but the lantern-kicking cow detail came from a reporter, Michael Ahern, who decades later openly admitted he and colleagues concocted the colourful story to make better copy. Catherine O'Leary, an Irish immigrant woman, was a convenient scapegoat at a time when anti-Irish and anti-immigrant feeling ran hot, and she spent the rest of her life hounded by a tale she always denied. An official inquiry could not establish the true cause, and in 1997 the Chicago City Council passed a resolution formally exonerating both her and the cow. So the most famous animal in disaster history was a newsroom fabrication aimed at an immigrant woman. Something started that barn fire. It almost certainly was not a cow with a grudge against a lantern.