Click on image to see it larger. Way cool!
I read a book about this guy. He compiled his famous map of the world even though he was not a scientist, traveler, explorer, or cartographer. He never left Venice in fact. But he compiled his map from all the information he could get his hands on and from talking to hundreds of sailors and others who had traveled around the (known) world at the time. Amazingly, it was the most accurate map at the time. Upside down for some reason, and with a big inlet in Africa that does not exist (or a river dividing South Africa from the rest of the continent, etc.) but more accurate than most maps at the time.