AFRAID OF THE UNKNOWN
Those things we have never seen or experienced can seem overwhelming. On the old maps, back before the world was understood in modern terms, cartographers, map makers, would put down what they knew, but at the edges of the map, beyond which they had no knowledge or understanding, they would often write, "Beyond here, there be dragons."
(Ed Rowell, in his sermon "Mary—A Song of Trust," PreachingToday.com)