American Museum of National History, New York City

The Gorgon Medusa, her hair a wild tumble of snakes, gazes humorlessly from a Carthaginian mosaic dating to almost 300 A.D. and now on view in Los Angeles. Images intended to ward off evil were common to mosaics in Roman-period Carthage. This Medusa, for example, was believed to have the power to turn to stone any would-be evildoers who looked upon it.