The document discusses theories about the Mona Lisa painting, including that she smiles because she was pregnant based on her swollen hands resting on her belly. It is also said that Leonardo painted it so that her smile disappears when looked at directly but reappears when looking elsewhere in the painting. The true state of mind of the Mona Lisa is unknown due to her mysterious smile that seems to convey different emotions. The painting was stolen from the Louvre in 1911 but was recovered that same December.

5.  To Yale University in the United States we come to explain
the research conducted there. They say the lady smiles
because she is expecting a child. One reason is that, as the
symptom of a pregnant woman, Lisa's hands are swollen. In
addition, how they rest on the belly gives a sense of
protection for your baby.
 It is said that Leonardo painted it having an effect by
which if you look directly the smile, it disappears and only
reappears when you notice any other part of the picture.
 Either way, it has never come to know the true state of
mind of the Mona Lisa. What lies behind this mysterious
and disconcerting smile that seems to look as mischievous,
protective, sad, calm or even malevolent.
 when the August 21, 1911 was stolen from the Louvre
Museum. The author of the theft would be a certain
Vincenzo Perugia, who managed to get the police in
December that year.