Detail from Fra Mauro's map, a work of unprecedented thoroughness and accuracy. PUBLIC DOMAIN If you had landed in Venice during the mid-15th century, you might have been accosted by a monk with a prominent nose and baggy, smurf-like hat. Ignoring your exhaustion and atrocious body odor after a long sea journey, he would have dragged you to a nearby tavern and cross-examined you about your travels. What was the weather like? What kind of precious gems were mined? What animals did you encounter, and how many heads did they have?The monk was Fra Mauro, a 15th-century version of Google...