The earth acts a bit like a giant bar magnet, with a magnetic north and south pole. These aren't in quite the same place as the poles on a map or globe.

The magnetic north pole is somewhere in the Canadian Artic. Pilots had tables that told them the different angle between where their compass pointed to (magnetic north) and the north pole.

This angle varies depending where you are in the world. It is called "variation".

{short description of image} The World