The Cottingley fairy hoax
snip
...
The story of the Cottingley fairies has always fascinated me—not because of the particulars of the case, but because of what it reveals about the life cycle of a lie. In contrast to other famous hoaxes, it doesn’t seem malicious, or even necessarily deliberate. Instead it seems to me to be a story about how a single, relatively small act of deception can lead a large group of people to lose control over the truth.
...