Cottingley Fairies

> In 1917, when the first two photographs were taken, Elsie was 16 years old and Frances was 9. The pictures came to the attention of writer Sir Arthur Conan Doyle, who used them to illustrate an article on fairies he had been commissioned to write for the Christmas 1920 edition of The Strand Magazine.

Impressive how naive people were. Actually I can't say they were specially naive or that we simply live in a world where better access to information is possible. Still, people continue falling for conspiracy theories.