A cow took the blame for the Great Chicago Fire for over a century

The story that Mrs. O'Leary's cow kicked over a lantern and started the Great Chicago Fire of 1871, which killed around 300 people and destroyed thousands of buildings, was invented by a newspaper reporter who later admitted he made it up for a better story. The Chicago City Council formally exonerated the cow in 1997.

— Wikipedia contributors, Great Chicago Fire — 1871; Chicago City Council resolution, 1997