Users of the program can turn the ad blocker on and transform the ads into blank spaces.

CNN: Cyber 'junkbusters' target Internet ads

But of course the truth is this story began centuries ago, when horsemen descended to the plains from a lost kingdom called Futa Djallon, long before Europe's map makers turned their minds to the niggling problem of how to fill those blank spaces.

NPR: 'Ancestor Stones:' Life and War in Sierra Leone