#13: Rupes Nigra at the North Pole
A black magnetic mountain at the top of the world sounds like something from a fantasy novel, yet it appeared in serious geographic tradition. Renaissance maps sometimes showed Rupes Nigra near the North Pole, imagined as a force that explained why compass needles pointed north. The idea tried to solve a real problem with the knowledge available at the time. Compass behavior was mysterious, and a magnetic mountain gave that mystery a location.
