Leonardo da Vinci's 'Mona Lisa' is perhaps the most famous painting in the world, yet viewers often notice a strange omission: she appears to have no eyebrows or eyelashes. For centuries, critics debated whether this was a fashion choice of the 16th century or a deliberate artistic statement. However, in 2007, ultra-high-resolution scans by French engineer Pascal Cotte revealed that Leonardo had indeed painted them. Over centuries of cleaning and restoration, the pigments used for the fine hairs had faded or been accidentally scrubbed away. The painting is also famous for the 'sfumato' technique, a method of blending colors and tones so subtly that there is no perceptible transition between colors. This creates the 'smoky' effect that gives the subject her enigmatic expression. Currently housed in the Louvre, the painting continues to be a subject of intense study for both art historians and digital conservators seeking to uncover the original layers of Leonardo's masterpiece.