Carlo Crivelli's 1486 painting, "The Annunciation," is surely one of the better-known works of the Renaissance. (It even made the cover of reason magazine a while back.) Now, somebody thinks the famous canvas, along with other Renaissance paintings, tapestries, and frescoes, might contain UFO images.
As it happens, all but one of the "extraterrestrial" details on the page are part of images depicting Jesus and Mary; an alternate view of the curious details is that they are intended as divine portents rather than as spaceships. Those in search of a good mystery, however, don't have far to go: Divine portents themselves are the subject of limitless dissection.