Was the Mona Lisa one of the earliest 3D artworks? Scientists studying the painting and a slightly different version possibly painted by Da Vinci or his students think the intent might have been to create a stereoscopic pair. From Discovery News:
(The University of Bamberg researchers) found that the horizontal difference between the two paintings was about 2.7 inches (69 millimeters), which is close to the average distance between a person’s two eyes. (When a person observes an object, each eye sees a slightly different perspective of the object, both of which are sent to the brain and transformed into the three-dimensional representation of the object that we “see.”)
(Discovery News, thanks Bob Pescovitz!)