<P> In December 2015, it was reported that French scientist Pascal Cotte had found a hidden portrait underneath the surface of the painting using reflective light technology . The portrait is an underlying image of a model looking off to the side . Having been given access to the painting by Louvre in 2004, Cotte spent ten years using layer amplification methods to study the painting . According to Cotte, the underlying image is Leonardo's original Mona Lisa . </P> <P> However, this portrait does not fit with the description of the painting in the historical records: Both Giorgio Vasari and Gian Paolo Lomazzo describe the subject as smiling; the subject in Cotte's portrait displays no smile . In addition, the portrait lacks the flanking columns drawn by Raphael in his c. 1504 sketch of Mona Lisa . Moreover, Cotte admits that his reconstitution had been carried out only in support of his hypotheses and should not be considered a real painting; he stresses that the images never existed . Kemp is also adamant that Cotte's images in no way establish the existence of a separate underlying portrait . </P> <P> On 21 August 1911, the painting was stolen from the Louvre . The theft was not discovered until the next day, when painter Louis Béroud walked into the museum and went to the Salon Carré where the Mona Lisa had been on display for five years, only to find four iron pegs on the wall . Béroud contacted the head of the guards, who thought the painting was being photographed for promotional purposes . A few hours later, Béroud checked back with the Section Chief of the Louvre who confirmed that the Mona Lisa was not with the photographers . The Louvre was closed for an entire week during the investigation . </P> <P> French poet Guillaume Apollinaire, who had once called for the Louvre to be "burnt down", came under suspicion and was arrested and imprisoned . Apollinaire implicated his friend Pablo Picasso, who was brought in for questioning . Both were later exonerated . Two years later the thief revealed himself . Louvre employee Vincenzo Peruggia had stolen the Mona Lisa by entering the building during regular hours, hiding in a broom closet, and walking out with it hidden under his coat after the museum had closed . Peruggia was an Italian patriot who believed Leonardo's painting should have been returned for display in an Italian museum . </P>

What is the speciality of mona lisa smile