The Mona Lisa became the world's most famous painting after it was stolen in 1911

On 21 August 1911, an Italian handyman named Vincenzo Peruggia lifted the Mona Lisa off a Louvre wall, hid it under his clothes, and walked out. He had briefly worked at the museum and even helped build the painting’s protective case, so he knew exactly how to remove it.

The theft caused a sensation. Newspapers worldwide ran the story for months, and the police flailed for suspects — at one point briefly arresting the painter Pablo Picasso and the poet Guillaume Apollinaire, both questioned and quickly released. Meanwhile crowds queued to stare at the bare wall where the portrait had hung. A painting admired mainly by specialists was suddenly known to everyone.

Peruggia kept it hidden in his Paris apartment for about two years. His motive was nationalist: he claimed he wanted to “return” the painting to Italy, wrongly believing Napoleon had looted it from his homeland (in fact Leonardo himself brought it to France). He was caught in 1913 when he tried to sell it to a dealer in Florence, and his patriotic story won him sympathy — he served a light sentence of roughly seven months and was hailed as a hero by some Italians.

Before its return, the recovered painting toured Italy in 1914, and the empty-wall spectacle had drawn bigger crowds than the picture itself ever had.

Guinness World Records lists the Mona Lisa as the most valuable object ever stolen — a status the theft itself helped create.