BBC:

In The Coming of Fairies, Arthur Conan Doyle claimed to be setting out the evidence for a race of magical beings, visible only to a chosen few. For the past five years, the writer and doctor had been studying a series of photographs that appeared to have captured this ‘subhuman race’ frolicking in a brook in Yorkshire – and he was now convinced of their authenticity.

The photos were a hoax – a schoolgirl prank that duped many people besides Conan Doyle. But how could someone so intelligent have fallen for such an obvious scam?

I’ve read various versions of this story for years. It’s always fascinating and an instructive lesson that everyone can be fooled if they want to be.