People looking at Mona Lisa believe that she looks at them from every direction they will look at her. However in a numerical survey I have conducted, that has never been done before, 500 people were asked to look at her from right, front and left sides. The results negate the well-known myth that Mona Lisa looks at the observer from all directions viewed where only 65% confirm that she was looking at them from all directions. Likewise, 93% confirmed that Mona Lisa was looking at them while viewing at her from right, 72% when viewing at her from front and 78% when viewing at her from left. The illustration demonstrates what they observer as seen from each direction. A thorough analysis of the subject brought me to extend and formulate a principle that I named “Mona Lisa’s gaze principle” which fits each element in a picture - portrait, wall in a construction, details in a landscape and the like. This principle guides also people how to look at pictures. According to this principle: “If you look at any detail in a picture and this detail turns to you from certain direction, it will turn to you from each direction you view it: from right, from front, from left, from above and from below. However, if from your looking direction the element does not turn to you, it will never turn to you.” Hence, I suggest to an observer of every picture