Question: when was the last time the mona lisa was stolen

title: Vincenzo Peruggia
text: In 1911 , Peruggia perpetrated what has been described as the greatest art theft of the 20th century . It was a police theory that the former Louvre worker hid inside the museum on Sunday , August 20 , knowing the museum would be closed the following day . But , according to Peruggia 's interrogation in Florence after his arrest , he entered the museum on Monday , August 21 around 7 am , through the door where the other Louvre workers were entering . He said he wore one of the white smocks that museum employees customarily wore and was indistinguishable from the other workers . When the Salon Carré , where the Mona Lisa hung , was empty , he lifted the painting off the four iron pegs that secured it to the wall and took it to a nearby service staircase . There , he removed the protective case and frame . Some people report that he concealed the painting ( which Leonardo painted on wood ) under his smock . But Peruggia was only 5 ft 3 in ( 160 cm ) , and the Mona Lisa measures approx. 21 in × 30 in ( 53 cm × 77 cm ) , so it would not fit under a smock worn by someone his size . Instead , he said he took off his smock and wrapped it around the painting , tucked it under his arm , and left the Louvre through the same door he had entered .