Is the painting considered Leonardo’s greatest work, on a wall behind another painting by Vasari? A scientist using sophisticated scanners thinks he’s discovered it. “We looked through Vasari’s painted walls with a low-frequency sonogram machine. On the west wall we found nothing really significant. But on the east wall, beneath the Battle of Marciano, we spotted a 16-centimeter cavity. It is very likely that Vasari created it to protect Leonardo’s work. Amazingly, this hollow space is right under Vasari’s hint ‘seek and you shall find.’ “